kernel.cpp

#include <stddef.h>
#include <stdint.h>

extern "C" {
void *malloc(size_t size);
void free(void *ptr);

// Date/Time
struct Time {
  uint8_t hour;
  uint8_t minute;
  uint8_t second;
};
Time get_time();

// C-String und Speicherfunktionen
int string_length(const char *str);
void string_copy(char *dest, const char *src);
bool string_compare(const char *s1, const char *s2);
void memset(void *ptr, uint8_t value, uint32_t size);
void memcpy(void *dest, const void *src, uint32_t size);
}

// Minimal heap implementation (for example only)
// Increased heap size for safety
static uint8_t kernel_heap[16 * 1024 * 1024]; // 16 MB heap
static size_t heap_top = 0;

extern "C" void *malloc(size_t size) {
  if (heap_top + size >= sizeof(kernel_heap))
    return nullptr;
  void *ptr = &kernel_heap[heap_top];
  heap_top += size;
  return ptr;
}

extern "C" void free(void *) {
  // no-op for now
}

// C++ operators
void *operator new(size_t size) { return malloc(size); }
void *operator new[](size_t size) { return malloc(size); }
void operator delete(void *p) noexcept { free(p); }
void operator delete[](void *p) noexcept { free(p); }

// Multiboot-Header-Struktur
struct multiboot_header {
  uint32_t magic;
  uint32_t flags;
  uint32_t checksum;
  // Padding/Address fields (must be present to reach offset 32 for graphics
  // fields)
  uint32_t header_addr;
  uint32_t load_addr;
  uint32_t load_end_addr;
  uint32_t bss_end_addr;
  uint32_t entry_addr;
  // Graphics fields (Offset 32)
  uint32_t mode_type;
  uint32_t width;
  uint32_t height;
  uint32_t depth;
};

const uint32_t MULTIBOOT_MAGIC = 0x1BADB002;
// Flags: Modules aligned (1), Mem info (2), Graphics mode (4)
const uint32_t MULTIBOOT_FLAGS = 0x00000007;
const uint32_t MULTIBOOT_CHECKSUM = -(MULTIBOOT_MAGIC + MULTIBOOT_FLAGS);

__attribute__((section(".multiboot_header"))) struct multiboot_header header = {
    .magic = MULTIBOOT_MAGIC,
    .flags = MULTIBOOT_FLAGS,
    .checksum = MULTIBOOT_CHECKSUM,
    .header_addr = 0,
    .load_addr = 0,
    .load_end_addr = 0,
    .bss_end_addr = 0,
    .entry_addr = 0,
    .mode_type = 0, // 0 = linear graphics mode
    .width = 800,
    .height = 600,
    .depth = 32};

// VBE Info Structures
struct vbe_mode_info {
  uint16_t attributes;
  uint8_t win_a, win_b;
  uint16_t granularity;
  uint16_t winsize;
  uint16_t segment_a, segment_b;
  uint32_t win_funcptr;
  uint16_t bytes_per_scanline;
  uint16_t x_res, y_res;
  uint8_t x_charsize, y_charsize, planes, bpp, banks;
  uint8_t memory_model, bank_size, image_pages, reserved0;
  uint8_t red_mask, red_position;
  uint8_t green_mask, green_position;
  uint8_t blue_mask, blue_position;
  uint8_t reserved_mask, reserved_position;
  uint8_t direct_color_attributes;
  uint32_t framebuffer;
  uint32_t off_screen_mem_off;
  uint16_t off_screen_mem_size;
  uint8_t reserved1[206];
} __attribute__((packed));

struct multiboot_info {
  uint32_t flags;
  uint32_t mem_lower;
  uint32_t mem_upper;
  uint32_t boot_device;
  uint32_t cmdline;
  uint32_t mods_count;
  uint32_t mods_addr;
  uint32_t syms[4];
  uint32_t mmap_length;
  uint32_t mmap_addr;
  uint32_t drives_length;
  uint32_t drives_addr;
  uint32_t config_table;
  uint32_t boot_loader_name;
  uint32_t apm_table;
  uint32_t vbe_control_info;
  uint32_t vbe_mode_info;
  uint16_t vbe_mode;
  uint16_t vbe_interface_seg;
  uint16_t vbe_interface_off;
  uint16_t vbe_interface_len;

  // Framebuffer info (Bit 12)
  uint64_t framebuffer_addr;
  uint32_t framebuffer_pitch;
  uint32_t framebuffer_width;
  uint32_t framebuffer_height;
  uint8_t framebuffer_bpp;
  uint8_t framebuffer_type;
  uint8_t color_info[6];
} __attribute__((packed));

struct Graphics {
  uint32_t *framebuffer;
  uint32_t width;
  uint32_t height;
  uint32_t pitch;
  bool active;
} screen;

extern "C" void put_pixel(int x, int y, uint32_t color) {
  if (!screen.active || x < 0 || (uint32_t)x >= screen.width || y < 0 ||
      (uint32_t)y >= screen.height)
    return;
  screen.framebuffer[y * (screen.pitch / 4) + x] = color;
}

uint32_t system_ram_mb = 0;

extern "C" uint32_t get_total_ram_mb() { return system_ram_mb; }

// ============================================================================
// I/O PORT FUNKTIONEN
// ============================================================================

extern "C" uint8_t inb(uint16_t port) {
  uint8_t ret;
  asm volatile("inb %1, %0" : "=a"(ret) : "Nd"(port));
  return ret;
}

extern "C" uint16_t inw(uint16_t port) {
  uint16_t ret;
  asm volatile("inw %1, %0" : "=a"(ret) : "Nd"(port));
  return ret;
}

extern "C" uint32_t inl(uint16_t port) {
  uint32_t ret;
  asm volatile("inl %1, %0" : "=a"(ret) : "Nd"(port));
  return ret;
}

extern "C" void outb(uint16_t port, uint8_t val) {
  asm volatile("outb %0, %1" : : "a"(val), "Nd"(port));
}

extern "C" void outw(uint16_t port, uint16_t val) {
  asm volatile("outw %0, %1" : : "a"(val), "Nd"(port));
}

extern "C" void outl(uint16_t port, uint32_t val) {
  asm volatile("outl %0, %1" : : "a"(val), "Nd"(port));
}

extern "C" void insl(uint16_t port, void *addr, uint32_t count) {
  asm volatile("cld; rep insl"
               : "+D"(addr), "+c"(count)
               : "d"(port)
               : "memory");
}

extern "C" void outsl(uint16_t port, const void *addr, uint32_t count) {
  asm volatile("cld; rep outsl"
               : "+S"(addr), "+c"(count)
               : "d"(port)
               : "memory");
}

// Verbesserte Delay-Funktion (wichtig!)
void delay(uint32_t count) {
  for (volatile uint32_t i = 0; i < count * 1000000; ++i) {
    asm volatile("nop");
  }
}

// Kürzere Delay für I/O-Operationen
void io_wait() {
  for (volatile int i = 0; i < 4; ++i) {
    inb(0x80); // Port 0x80 für I/O-Delay
  }
}

// ============================================================================
// GRUNDLEGENDE VGA FUNKTIONEN
// ============================================================================

void print_char(int row, int col, char character, uint16_t color) {
  if (row < 0 || row >= 25 || col < 0 || col >= 80)
    return;
  uint16_t *video_memory = (uint16_t *)0xb8000;
  int offset = row * 80 + col;
  video_memory[offset] = (color << 8) | character;
}

void print_string(int row, int col, const char *str, uint16_t color);

void print_string(int row, int col, const char *str, uint16_t color) {
  int i = 0;
  while (str[i] != '\0') {
    print_char(row, col + i, str[i], color);
    i++;
  }
}

void print_string_centered(int row, const char *str, uint16_t color) {
  int len = string_length(str);
  int col = (80 - len) / 2;
  print_string(row, col, str, color);
}

void clear_screen(uint16_t color) {
  uint16_t *video_memory = (uint16_t *)0xb8000;
  for (int i = 0; i < 80 * 25; ++i) {
    video_memory[i] = (color << 8) | ' ';
  }
}

// ============================================================================
// MOUSE DRIVER & WALLPAPER
// ============================================================================

int mouse_x = 40;
int mouse_y = 12;
int global_mouse_speed = 2; // 0=Slowest, 1=Slow, 2=Normal, 3=Fast
uint8_t mouse_cycle = 0;
int8_t mouse_byte[3];
bool mouse_left = false;
bool mouse_right = false;
bool mouse_middle = false;
bool show_wallpaper = false;

void mouse_wait(uint8_t type) {
  uint32_t timeout = 100000;
  if (type == 0) {
    while (timeout--) {
      if ((inb(0x64) & 1) == 1)
        return;
    }
  } else {
    while (timeout--) {
      if ((inb(0x64) & 2) == 0)
        return;
    }
  }
}

void mouse_write(uint8_t w) {
  mouse_wait(1);
  outb(0x64, 0xD4);
  mouse_wait(1);
  outb(0x60, w);
}

uint8_t mouse_read() {
  mouse_wait(0);
  return inb(0x60);
}

void init_mouse() {
  mouse_wait(1);
  outb(0x64, 0xA8);
  mouse_wait(1);
  outb(0x64, 0x20);
  mouse_wait(0);
  uint8_t status = inb(0x60) | 2;
  mouse_wait(1);
  outb(0x64, 0x60);
  mouse_wait(1);
  outb(0x60, status);
  mouse_write(0xF6);
  mouse_read();
  mouse_write(0xF4);
  mouse_read();
}

void handle_mouse_byte(uint8_t b) {
  if (mouse_cycle == 0) {
    if ((b & 0x08) == 0x08) {
      mouse_byte[0] = b;
      mouse_cycle++;
    }
  } else if (mouse_cycle == 1) {
    mouse_byte[1] = b;
    mouse_cycle++;
  } else {
    mouse_byte[2] = b;
    mouse_cycle = 0;

    mouse_left = mouse_byte[0] & 1;
    mouse_right = mouse_byte[0] & 2;
    mouse_middle = mouse_byte[0] & 4;

    int dx = (int8_t)mouse_byte[1];
    int dy = (int8_t)mouse_byte[2];
    int divisor = 4 - global_mouse_speed;
    if (divisor < 1) divisor = 1;
    mouse_x += dx / divisor;
    mouse_y -= dy / divisor;

    if (screen.active) {
      if (mouse_x < 0)
        mouse_x = 0;
      if ((uint32_t)mouse_x > screen.width - 1)
        mouse_x = screen.width - 1;
      if (mouse_y < 0)
        mouse_y = 0;
      if ((uint32_t)mouse_y > screen.height - 1)
        mouse_y = screen.height - 1;
    } else {
      if (mouse_x < 0)
        mouse_x = 0;
      if (mouse_x > 79)
        mouse_x = 79;
      if (mouse_y < 0)
        mouse_y = 0;
      if (mouse_y > 24)
        mouse_y = 24;
    }
  }
}

void draw_wallpaper_text() {
  clear_screen(0x20); // Green bg
  // Daisy Field Pattern
  for (int y = 0; y < 25; y++) {
    for (int x = 0; x < 80; x++) {
      int seed = (x * 37 + y * 89);
      if (seed % 17 == 0) {
        print_char(y, x, 'o', 0x2E); // Yellow center
      } else if ((seed % 17) >= 1 && (seed % 17) <= 4) {
        print_char(y, x, '*', 0x2F); // White petals
      }
    }
  }
}

// ============================================================================
// C-STRING UND SPEICHER FUNKTIONEN (JETZT EXTERN C)
// ============================================================================
extern "C" {
int string_length(const char *str) {
  int len = 0;
  while (str[len] != '\0')
    len++;
  return len;
}

void string_copy(char *dest, const char *src) {
  int i = 0;
  while (src[i] != '\0') {
    dest[i] = src[i];
    i++;
  }
  dest[i] = '\0';
}

bool string_compare(const char *s1, const char *s2) {
  int i = 0;
  while (s1[i] != '\0' && s2[i] != '\0') {
    if (s1[i] != s2[i])
      return false;
    i++;
  }
  return s1[i] == s2[i];
}

void memset(void *ptr, uint8_t value, uint32_t size) {
  uint8_t *p = (uint8_t *)ptr;
  for (uint32_t i = 0; i < size; i++) {
    p[i] = value;
  }
}

void memcpy(void *dest, const void *src, uint32_t size) {
  uint8_t *d = (uint8_t *)dest;
  const uint8_t *s = (const uint8_t *)src;
  for (uint32_t i = 0; i < size; i++) {
    d[i] = s[i];
  }
}
} // Ende extern "C"

const char *get_filename_ext(const char *filename) {
  const char *dot = nullptr;
  while (*filename) {
    if (*filename == '.')
      dot = filename;
    filename++;
  }
  return dot ? dot + 1 : "";
}

// ============================================================================
// RTC (REAL TIME CLOCK)
// ============================================================================

uint8_t get_rtc_register(int reg) {
  outb(0x70, reg);
  return inb(0x71);
}

extern "C" Time get_time() {
  Time t;
  t.second = get_rtc_register(0x00);
  t.minute = get_rtc_register(0x02);
  t.hour = get_rtc_register(0x04);

  // BCD conversion
  t.second = (t.second & 0x0F) + ((t.second / 16) * 10);
  t.minute = (t.minute & 0x0F) + ((t.minute / 16) * 10);
  t.hour = ((t.hour & 0x0F) + ((t.hour & 0x70) / 16) * 10) | (t.hour & 0x80);

  return t;
}

// ============================================================================

// Dummy-Struktur, um FAT-Treiber-Signatur anzupassen
struct ATADevice {
  uint16_t io_base;
  uint16_t control_base;
  uint8_t drive;
  bool present;
  uint32_t size_sectors;
};

// Es gibt nur noch die RAM-Disk
ATADevice *active_disk = nullptr; // Zeigt auf die RAM-Disk

// +++ BEGINN RAM-DISK IMPLEMENTIERUNG +++
const size_t RAMDISK_SIZE_BYTES = 800 * 1024; // 800KB
const size_t RAMDISK_SIZE_SECTORS = RAMDISK_SIZE_BYTES / 512;
uint8_t *ramdisk_storage = nullptr; // Zeiger auf den Speicher der RAM-Disk
ATADevice ramdisk_device;           // Ein virtuelles ATADevice für die RAM-Disk
#define RAMDISK_MAGIC_IO 0xDEAD     // Eindeutige ID statt I/O-Port
#define SECTOR_SIZE 512             // Definiert hier, da es global genutzt wird
// +++ ENDE RAM-DISK IMPLEMENTIERUNG +++

// ============================================================================
// ATA PIO DRIVER (HDD SUPPORT)
// ============================================================================

bool ata_identify(ATADevice *dev) {
  if (dev->io_base == RAMDISK_MAGIC_IO)
    return true;

  // Select Drive
  outb(dev->io_base + 6, dev->drive == 0 ? 0xA0 : 0xB0);
  // Zero Sectorcount & LBA
  outb(dev->io_base + 2, 0);
  outb(dev->io_base + 3, 0);
  outb(dev->io_base + 4, 0);
  outb(dev->io_base + 5, 0);
  // Send Command
  outb(dev->io_base + 7, 0xEC); // IDENTIFY

  // Read Status
  uint8_t status = inb(dev->io_base + 7);
  if (status == 0)
    return false; // No drive

  // Poll until ready or error
  while (1) {
    status = inb(dev->io_base + 7);
    if ((status & 1))
      return false; // ERR
    if ((status & 8))
      break; // DRQ ready
  }

  // Read 256 words (discard for now, just checking presence)
  for (int i = 0; i < 256; i++)
    inw(dev->io_base);

  dev->present = true;
  dev->size_sectors = 0; // TODO: Parse size from identify data
  // For now assume standard size or read from MBR/Partition table later
  // Actually for FAT16 minimal support we just need read/write.
  return true;
}

void ata_wait_400ns(uint16_t io_base) {
  inb(io_base + 7);
  inb(io_base + 7);
  inb(io_base + 7);
  inb(io_base + 7);
}

// 28-bit LBA PIO Read
bool ata_read_sector_pio(ATADevice *dev, uint32_t lba, uint8_t *buffer) {
  // 0xE0 for Master, 0xF0 for Slave + upper 4 bits of LBA
  uint8_t drive_head = 0xE0 | (dev->drive << 4) | ((lba >> 24) & 0x0F);

  outb(dev->io_base + 6, drive_head); // Drive/Head
  outb(dev->io_base + 2, 1);          // Count = 1
  outb(dev->io_base + 3, (uint8_t)lba);
  outb(dev->io_base + 4, (uint8_t)(lba >> 8));
  outb(dev->io_base + 5, (uint8_t)(lba >> 16));
  outb(dev->io_base + 7, 0x20); // COMMAND READ SECTORS

  // Poll
  while (1) {
    uint8_t status = inb(dev->io_base + 7);
    if (status & 1)
      return false; // ERR
    if (status & 8)
      break; // DRQ
  }

  // Read Data
  insl(dev->io_base, buffer, 128); // Read 128 uint32s -> 512 bytes
  ata_wait_400ns(dev->io_base);
  return true;
}

// 28-bit LBA PIO Write
bool ata_write_sector_pio(ATADevice *dev, uint32_t lba, const uint8_t *buffer) {
  uint8_t drive_head = 0xE0 | (dev->drive << 4) | ((lba >> 24) & 0x0F);

  outb(dev->io_base + 6, drive_head);
  outb(dev->io_base + 2, 1);
  outb(dev->io_base + 3, (uint8_t)lba);
  outb(dev->io_base + 4, (uint8_t)(lba >> 8));
  outb(dev->io_base + 5, (uint8_t)(lba >> 16));
  outb(dev->io_base + 7, 0x30); // COMMAND WRITE SECTORS

  // Poll
  while (1) {
    uint8_t status = inb(dev->io_base + 7);
    if (status & 1)
      return false;
    if (status & 8)
      break;
  }

  // Write Data
  outsl(dev->io_base, buffer, 128);

  // Flush / Wait
  outb(dev->io_base + 7, 0xE7); // CACHE FLUSH
  while (inb(dev->io_base + 7) & 0x80)
    ; // Wait BSY

  return true;
}

bool ata_read_sector(ATADevice *dev, uint32_t lba, uint8_t *buffer) {
  if (dev->io_base == RAMDISK_MAGIC_IO) {
    if (!dev->present || lba >= dev->size_sectors)
      return false;
    uint32_t offset = lba * SECTOR_SIZE;
    memcpy(buffer, &ramdisk_storage[offset], SECTOR_SIZE);
    return true;
  } else {
    // HDD PIO Read
    return ata_read_sector_pio(dev, lba, buffer);
  }
}

bool ata_write_sector(ATADevice *dev, uint32_t lba, const uint8_t *buffer) {
  if (dev->io_base == RAMDISK_MAGIC_IO) {
    if (!dev->present || lba >= dev->size_sectors)
      return false;
    uint32_t offset = lba * SECTOR_SIZE;
    memcpy(&ramdisk_storage[offset], buffer, SECTOR_SIZE);
    return true;
  } else {
    // HDD PIO Write
    return ata_write_sector_pio(dev, lba, buffer);
  }
}

// ============================================================================
// FAT16 DATEISYSTEM
// ============================================================================

#define MAX_FILES 64
#define MAX_FILENAME 12

struct PartitionEntry {
  uint8_t bootable;
  uint8_t start_head;
  uint8_t start_sect_cyl;
  uint8_t start_cyl_low;
  uint8_t system_id;
  uint8_t end_head;
  uint8_t end_sect_cyl;
  uint8_t end_cyl_low;
  uint32_t start_lba;
  uint32_t total_sectors;
} __attribute__((packed));

struct MBR {
  uint8_t bootstrap[446];
  PartitionEntry partitions[4];
  uint16_t signature;
} __attribute__((packed));

struct BootSector {
  uint8_t jump[3];
  char oem[8];
  uint16_t bytes_per_sector;
  uint8_t sectors_per_cluster;
  uint16_t reserved_sectors;
  uint8_t fat_count;
  uint16_t root_entry_count;
  uint16_t total_sectors_16;
  uint8_t media_type;
  uint16_t sectors_per_fat_16;
  uint16_t sectors_per_track;
  uint16_t head_count;
  uint32_t hidden_sectors;
  uint32_t total_sectors_32;
  // FAT16/12 specific
  uint8_t drive_number;
  uint8_t reserved1;
  uint8_t boot_signature;
  uint32_t volume_id;
  char volume_label[11];
  char fs_type[8];
} __attribute__((packed));

struct DirEntry {
  char filename[11];
  uint8_t attributes;
  uint8_t reserved;
  uint8_t creation_time_ms;
  uint16_t creation_time;
  uint16_t creation_date;
  uint16_t last_access_date;
  uint16_t first_cluster_high;
  uint16_t last_modified_time;
  uint16_t last_modified_date;
  uint16_t first_cluster_low;
  uint32_t file_size;
} __attribute__((packed));

struct FileEntry {
  char name[MAX_FILENAME + 1];
  uint32_t size;
  bool is_directory;
  uint32_t first_cluster;
};

FileEntry file_cache[MAX_FILES];
int file_count = 0;

BootSector boot_sector;
uint8_t sector_buffer[SECTOR_SIZE];
bool fs_mounted = false;

uint32_t active_partition_lba = 0;
uint32_t active_partition_sectors = 0;

uint32_t fat_begin_lba = 0;
uint32_t cluster_begin_lba = 0;
uint32_t sectors_per_cluster = 0;
uint32_t root_dir_lba = 0;
uint32_t root_dir_sectors = 0;
uint32_t root_dir_first_cluster = 0;

bool format_fat16(ATADevice *dev, uint32_t offset, uint32_t size_sectors) {
  if (!dev->present)
    return false;

  // Initialisiere Boot Sector
  memset(&boot_sector, 0, sizeof(BootSector));

  boot_sector.jump[0] = 0xEB;
  boot_sector.jump[1] = 0x3C;
  boot_sector.jump[2] = 0x90;

  memcpy(boot_sector.oem, "MILLAFAT", 8);
  boot_sector.bytes_per_sector = 512;
  boot_sector.sectors_per_cluster = 8;
  boot_sector.reserved_sectors = 1;
  boot_sector.fat_count = 2;
  boot_sector.root_entry_count = 512;
  boot_sector.media_type = 0xF8;
  boot_sector.sectors_per_track = 63;
  boot_sector.head_count = 255;
  boot_sector.hidden_sectors = offset;

  // Setze Sektorgrößen
  uint32_t total_sectors = size_sectors;
  if (total_sectors < 0x10000) {
    boot_sector.total_sectors_16 = (uint16_t)total_sectors;
    boot_sector.total_sectors_32 = 0;
  } else {
    boot_sector.total_sectors_16 = 0;
    boot_sector.total_sectors_32 = total_sectors;
  }

  // Berechne Root-Verzeichnis-Größe
  root_dir_sectors = (boot_sector.root_entry_count * sizeof(DirEntry) +
                      boot_sector.bytes_per_sector - 1) /
                     boot_sector.bytes_per_sector;

  // Berechne FAT-Größe
  uint32_t data_sectors =
      total_sectors - boot_sector.reserved_sectors - root_dir_sectors;
  uint32_t cluster_count = data_sectors / boot_sector.sectors_per_cluster;
  uint32_t fat_size_sectors =
      (cluster_count * 2 + boot_sector.bytes_per_sector - 1) /
      boot_sector.bytes_per_sector;

  boot_sector.sectors_per_fat_16 = fat_size_sectors;

  boot_sector.drive_number = 0x80;
  boot_sector.boot_signature = 0x29;
  boot_sector.volume_id = 0x12345678;
  memcpy(boot_sector.volume_label, "MILLA OS   ", 11);
  memcpy(boot_sector.fs_type, "FAT16   ", 8);

  // Schreibe Boot Sector
  memset(sector_buffer, 0, SECTOR_SIZE);
  memcpy(sector_buffer, &boot_sector, sizeof(BootSector));
  sector_buffer[510] = 0x55;
  sector_buffer[511] = 0xAA;

  if (!ata_write_sector(dev, offset, sector_buffer))
    return false;

  // Initialisiere FAT (beide Kopien)
  memset(sector_buffer, 0, SECTOR_SIZE);
  ((uint16_t *)sector_buffer)[0] = 0xFFF8;
  ((uint16_t *)sector_buffer)[1] = 0xFFFF;

  uint32_t fat1_lba = offset + boot_sector.reserved_sectors;
  uint32_t fat2_lba = fat1_lba + boot_sector.sectors_per_fat_16;

  if (!ata_write_sector(dev, fat1_lba, sector_buffer))
    return false;
  if (!ata_write_sector(dev, fat2_lba, sector_buffer))
    return false;

  // Lösche restliche FAT Sektoren
  memset(sector_buffer, 0, SECTOR_SIZE);
  for (uint32_t i = 1; i < boot_sector.sectors_per_fat_16; i++) {
    ata_write_sector(dev, fat1_lba + i, sector_buffer);
    ata_write_sector(dev, fat2_lba + i, sector_buffer);
  }

  // Initialisiere Root Directory
  uint32_t root_lba =
      fat1_lba + (boot_sector.fat_count * boot_sector.sectors_per_fat_16);

  memset(sector_buffer, 0, SECTOR_SIZE);
  for (uint32_t i = 0; i < root_dir_sectors; i++) {
    if (!ata_write_sector(dev, root_lba + i, sector_buffer))
      return false;
  }

  return true;
}

bool format_mbr(ATADevice *dev) {
  if (!dev->present)
    return false;
  memset(sector_buffer, 0, SECTOR_SIZE);
  MBR *mbr = (MBR *)sector_buffer;
  mbr->signature = 0xAA55;

  // Create one large partition
  mbr->partitions[0].bootable = 0x80;
  mbr->partitions[0].system_id = 0x06; // FAT16
  mbr->partitions[0].start_lba = 63;   // Standard offset
  mbr->partitions[0].total_sectors = dev->size_sectors - 63;

  return ata_write_sector(dev, 0, sector_buffer);
}

bool mount_fat16(ATADevice *dev, uint32_t offset) {
  if (!dev->present)
    return false;

  if (!ata_read_sector(dev, offset, sector_buffer))
    return false;

  // Überprüfe die Magische Zahl
  if (sector_buffer[510] != 0x55 || sector_buffer[511] != 0xAA)
    return false;

  memcpy(&boot_sector, sector_buffer, sizeof(BootSector));

  if (boot_sector.bytes_per_sector != 512)
    return false;
  if (boot_sector.fat_count == 0)
    return false;

  fat_begin_lba = offset + boot_sector.reserved_sectors;

  // Berechne Positionen für FAT16
  root_dir_sectors = (boot_sector.root_entry_count * sizeof(DirEntry) +
                      boot_sector.bytes_per_sector - 1) /
                     boot_sector.bytes_per_sector;
  root_dir_lba =
      fat_begin_lba + (boot_sector.fat_count * boot_sector.sectors_per_fat_16);
  cluster_begin_lba = root_dir_lba + root_dir_sectors;

  sectors_per_cluster = boot_sector.sectors_per_cluster;
  root_dir_first_cluster = 0;

  active_partition_lba = offset;

  fs_mounted = true;
  return true;
}

uint32_t cluster_to_lba(uint32_t cluster) {
  return cluster_begin_lba + (cluster - 2) * sectors_per_cluster;
}

uint32_t get_fat_entry(ATADevice *dev, uint32_t cluster) {
  uint32_t fat_offset = cluster * 2;
  uint32_t fat_sector = fat_begin_lba + (fat_offset / SECTOR_SIZE);
  uint32_t entry_offset = fat_offset % SECTOR_SIZE;

  if (!ata_read_sector(dev, fat_sector, sector_buffer))
    return 0xFFFF;

  return *((uint16_t *)&sector_buffer[entry_offset]);
}

void set_fat_entry(ATADevice *dev, uint32_t cluster, uint32_t value) {
  uint32_t fat_offset = cluster * 2;
  uint32_t fat_sector = fat_begin_lba + (fat_offset / SECTOR_SIZE);
  uint32_t entry_offset = fat_offset % SECTOR_SIZE;

  ata_read_sector(dev, fat_sector, sector_buffer);
  *((uint16_t *)&sector_buffer[entry_offset]) = value & 0xFFFF;
  ata_write_sector(dev, fat_sector, sector_buffer);

  // Update second FAT copy
  uint32_t fat2_sector = fat_sector + boot_sector.sectors_per_fat_16;
  ata_read_sector(dev, fat2_sector, sector_buffer);
  *((uint16_t *)&sector_buffer[entry_offset]) = value & 0xFFFF;
  ata_write_sector(dev, fat2_sector, sector_buffer);
}

uint32_t allocate_cluster(ATADevice *dev) {
  for (uint32_t cluster = 2; cluster < 0xFFF0; cluster++) {
    uint32_t entry = get_fat_entry(dev, cluster);
    if (entry == 0) {
      set_fat_entry(dev, cluster, 0xFFFF); // FAT16 EOF
      return cluster;
    }
  }
  return 0;
}

bool read_directory(ATADevice *dev, uint32_t cluster) {
  file_count = 0;

  if (cluster == 0) {
    for (uint32_t sec = 0; sec < root_dir_sectors; sec++) {
      if (!ata_read_sector(dev, root_dir_lba + sec, sector_buffer))
        return false;

      DirEntry *entries = (DirEntry *)sector_buffer;

      for (int i = 0; i < (SECTOR_SIZE / sizeof(DirEntry)); i++) {
        if (entries[i].filename[0] == 0x00)
          return true;
        if (entries[i].filename[0] == 0xE5)
          continue;
        if (entries[i].attributes == 0x0F)
          continue;

        if (file_count >= MAX_FILES)
          return true;

        int name_pos = 0;
        for (int j = 0; j < 8 && entries[i].filename[j] != ' '; j++) {
          file_cache[file_count].name[name_pos++] = entries[i].filename[j];
        }

        if (entries[i].filename[8] != ' ') {
          file_cache[file_count].name[name_pos++] = '.';
          for (int j = 8; j < 11 && entries[i].filename[j] != ' '; j++) {
            file_cache[file_count].name[name_pos++] = entries[i].filename[j];
          }
        }
        file_cache[file_count].name[name_pos] = '\0';

        file_cache[file_count].size = entries[i].file_size;
        file_cache[file_count].is_directory =
            (entries[i].attributes & 0x10) != 0;
        file_cache[file_count].first_cluster =
            ((uint32_t)entries[i].first_cluster_high << 16) |
            entries[i].first_cluster_low;
        file_count++;
      }
    }
  } else {
    while (cluster < 0xFFF8) {
      uint32_t lba = cluster_to_lba(cluster);

      for (uint8_t sec = 0; sec < sectors_per_cluster; sec++) {
        if (!ata_read_sector(dev, lba + sec, sector_buffer))
          return false;

        DirEntry *entries = (DirEntry *)sector_buffer;

        for (int i = 0; i < (SECTOR_SIZE / sizeof(DirEntry)); i++) {
          if (entries[i].filename[0] == 0x00)
            return true;
          if (entries[i].filename[0] == 0xE5)
            continue;
          if (entries[i].attributes == 0x0F)
            continue;

          if (file_count >= MAX_FILES)
            return true;

          int name_pos = 0;
          for (int j = 0; j < 8 && entries[i].filename[j] != ' '; j++) {
            file_cache[file_count].name[name_pos++] = entries[i].filename[j];
          }
          if (entries[i].filename[8] != ' ') {
            file_cache[file_count].name[name_pos++] = '.';
            for (int j = 8; j < 11 && entries[i].filename[j] != ' '; j++) {
              file_cache[file_count].name[name_pos++] = entries[i].filename[j];
            }
          }
          file_cache[file_count].name[name_pos] = '\0';
          file_cache[file_count].size = entries[i].file_size;
          file_cache[file_count].is_directory =
              (entries[i].attributes & 0x10) != 0;
          file_cache[file_count].first_cluster =
              ((uint32_t)entries[i].first_cluster_high << 16) |
              entries[i].first_cluster_low;
          file_count++;
        }
      }
      cluster = get_fat_entry(dev, cluster);
    }
  }
  return true;
}

int find_file(const char *name) {
  for (int i = 0; i < file_count; i++) {
    if (string_compare(file_cache[i].name, name)) {
      return i;
    }
  }
  return -1;
}

bool read_file(ATADevice *dev, uint32_t cluster, char *buffer,
               uint32_t max_size) {
  uint32_t pos = 0;

  while (cluster < 0xFFF8 && pos < max_size) {
    uint32_t lba = cluster_to_lba(cluster);

    for (uint8_t sec = 0; sec < sectors_per_cluster && pos < max_size; sec++) {
      if (!ata_read_sector(dev, lba + sec, sector_buffer))
        return false;

      uint32_t to_copy =
          (max_size - pos < SECTOR_SIZE) ? (max_size - pos) : SECTOR_SIZE;
      memcpy(buffer + pos, sector_buffer, to_copy);
      pos += to_copy;
    }

    cluster = get_fat_entry(dev, cluster);
  }

  // KORREKTUR: Stelle sicher, dass der Puffer nullterminiert ist,
  // wenn die Datei kleiner als der Puffer ist (und Platz dafür ist).
  if (pos < max_size) {
    buffer[pos] = '\0';
  } else if (max_size > 0) {
    buffer[max_size - 1] =
        '\0'; // Erzwinge Nullterminierung, falls max_size erreicht wurde
  }

  return true;
}

bool write_file(ATADevice *dev, const char *filename, const char *data,
                uint32_t size) {
  // Finde leeren Verzeichniseintrag (nur im Root-Verzeichnis)
  uint32_t dir_lba = root_dir_lba;

  int empty_entry = -1;
  uint32_t entry_lba = 0;

  // TODO: Diese Funktion sollte prüfen, ob die Datei bereits existiert.
  // Wenn ja, sollte sie die alte Cluster-Kette finden, alle Cluster
  // in der FAT als 'frei' (0) markieren und den Verzeichniseintrag
  // wiederverwenden, anstatt einen neuen zu suchen.
  // Die aktuelle Implementierung kann Dateien NICHT überschreiben.

  for (uint32_t sec = 0; sec < root_dir_sectors; sec++) {
    if (!ata_read_sector(dev, dir_lba + sec, sector_buffer))
      return false;

    DirEntry *entries = (DirEntry *)sector_buffer;
    for (int i = 0; i < (SECTOR_SIZE / sizeof(DirEntry)); i++) {
      if (entries[i].filename[0] == 0x00 || entries[i].filename[0] == 0xE5) {
        empty_entry = i;
        entry_lba = dir_lba + sec;
        break;
      }
    }
    if (empty_entry != -1)
      break;
  }

  if (empty_entry == -1)
    return false; // Kein Platz im Root-Verzeichnis

  // Alloziere Cluster für Dateidaten
  uint32_t file_cluster = allocate_cluster(dev);
  if (file_cluster == 0)
    return false; // Kein Speicherplatz (Cluster)

  // Schreibe Dateidaten
  uint32_t written = 0;
  uint32_t current_cluster = file_cluster;

  while (written < size) {
    uint32_t file_lba = cluster_to_lba(current_cluster);

    for (uint8_t sec = 0; sec < sectors_per_cluster && written < size; sec++) {
      memset(sector_buffer, 0, SECTOR_SIZE);
      uint32_t to_write =
          (size - written < SECTOR_SIZE) ? (size - written) : SECTOR_SIZE;
      memcpy(sector_buffer, data + written, to_write);

      if (!ata_write_sector(dev, file_lba + sec, sector_buffer))
        return false;
      written += to_write;
    }

    if (written < size) {
      uint32_t next_cluster = allocate_cluster(dev);
      if (next_cluster == 0)
        return false; // Kein Speicherplatz mehr
      set_fat_entry(dev, current_cluster, next_cluster);
      current_cluster = next_cluster;
    }
  }

  // Erstelle Verzeichniseintrag
  ata_read_sector(dev, entry_lba, sector_buffer);
  DirEntry *entries = (DirEntry *)sector_buffer;
  DirEntry *entry = &entries[empty_entry];

  memset(entry, 0, sizeof(DirEntry));

  // KORREKTUR: Parse Dateiname (8.3 Format, Großbuchstaben, Padding)
  memset(entry->filename, ' ', 11); // Mit Leerzeichen füllen

  int name_pos = 0;
  int ext_pos = 8;
  bool found_dot = false;

  for (int i = 0; filename[i] != '\0'; i++) {
    char c = filename[i];

    if (c == '.') {
      found_dot = true;
      continue;
    }

    // Konvertiere zu Großbuchstaben
    if (c >= 'a' && c <= 'z')
      c -= 32;

    if (found_dot) {
      if (ext_pos < 11) {
        entry->filename[ext_pos++] = c;
      }
    } else {
      if (name_pos < 8) {
        entry->filename[name_pos++] = c;
      }
    }
  }

  entry->attributes = 0x20; // Archive
  entry->first_cluster_high = (file_cluster >> 16) & 0xFFFF;
  entry->first_cluster_low = file_cluster & 0xFFFF;
  entry->file_size = size;

  return ata_write_sector(dev, entry_lba, sector_buffer);
}

// Initialisierung
ATADevice hdd_device;

void init_filesystem() {

  // +++ ERSTELLE RAM-DISK +++
  print_string(21, 10, "Creating RAM disk...", 0x0E);

  // Speicher allozieren (MUSS VOR ANDEREN MALLOCS PASSIEREN)
  ramdisk_storage = (uint8_t *)malloc(RAMDISK_SIZE_BYTES);

  if (ramdisk_storage == nullptr) {
    print_string(22, 10, "RAM disk creation failed! (Out of memory)", 0x0C);
    active_disk = nullptr;
  } else {
    // RAM-Disk mit 0 füllen (wichtig für leeres Dateisystem)
    memset(ramdisk_storage, 0, RAMDISK_SIZE_BYTES);

    // Virtuelles Gerät einrichten
    ramdisk_device.io_base = RAMDISK_MAGIC_IO; // Magische Zahl
    ramdisk_device.control_base = 0;
    ramdisk_device.drive = 0;
    ramdisk_device.present = true;
    ramdisk_device.size_sectors = RAMDISK_SIZE_SECTORS;

    active_disk = &ramdisk_device;
    print_string(22, 10, "RAM disk (800KB) created.", 0x0A);
  }
  // +++ ENDE RAM-DISK ERSTELLUNG +++

  // +++ HDD PROBE +++
  print_string(21, 45, "Probing HDD...", 0x0E);
  hdd_device.io_base = 0x1F0; // Primary
  hdd_device.control_base = 0x3F6;
  hdd_device.drive = 0; // Master
  hdd_device.present = false;

  if (ata_identify(&hdd_device)) {
    print_string(22, 45, "HDD Found (Master)", 0x0A);
    hdd_device.present = true;
    hdd_device.size_sectors = 131072; // Assume 64MB for now (TODO: Identify)
    // We don't mount it as active by default, user must switch
  } else {
    print_string(22, 45, "No HDD Found", 0x0C);
  }

  // Mount logic
  if (active_disk) {
    if (!mount_fat16(active_disk, 0)) {
      // Only format RAM disk automatically
      if (active_disk == &ramdisk_device) {
        print_string(23, 10, "Formatting RAM disk...    ", 0x0E);
        if (format_fat16(active_disk, 0, active_disk->size_sectors)) {
          mount_fat16(active_disk, 0);
          print_string(23, 10, "Format complete.          ", 0x0A);
        } else {
          print_string(23, 10, "Format failed!            ", 0x0C);
        }
      }
    }
  }

  // AUTO-MOUNT HDD if FAT exists
  if (hdd_device.present) {
    if (ata_read_sector(&hdd_device, 0, sector_buffer)) {
      if (sector_buffer[510] == 0x55 && sector_buffer[511] == 0xAA) {
        MBR *mbr = (MBR *)sector_buffer;
        for (int i = 0; i < 4; i++) {
          if (mbr->partitions[i].total_sectors > 0) {
            if (mount_fat16(&hdd_device, mbr->partitions[i].start_lba)) {
              active_disk = &hdd_device; // Prefer HDD if FAT exists
              print_string(23, 45, "HDD Partition Mounted    ", 0x0A);
              break;
            }
          }
        }
        // Also check LBA 0 for superfloppy
        if (!fs_mounted && mount_fat16(&hdd_device, 0)) {
          active_disk = &hdd_device;
          print_string(23, 45, "HDD Superfloppy Mounted  ", 0x0A);
        }
      }
    }
  }

  if (fs_mounted) {
    read_directory(active_disk, root_dir_first_cluster);
  }
  delay(1); // Kurze Pause
}

// ============================================================================
// GUI FUNKTIONEN
// ============================================================================

void draw_window(int start_row, int start_col, int height, int width,
                 const char *title, uint16_t border_color) {
  print_char(start_row, start_col, 201, border_color);
  for (int i = 1; i < width - 1; i++) {
    print_char(start_row, start_col + i, 205, border_color);
  }
  print_char(start_row, start_col + width - 1, 187, border_color);

  int title_len = string_length(title);
  if (title_len > 0) {
    int title_start = (width - title_len - 2) / 2;
    print_char(start_row, start_col + title_start, 185, border_color);
    print_string(start_row, start_col + title_start + 1, title, 0x0E);
    print_char(start_row, start_col + title_start + title_len + 1, 204,
               border_color);
  }

  for (int i = 1; i < height - 1; i++) {
    print_char(start_row + i, start_col, 186, border_color);
    print_char(start_row + i, start_col + width - 1, 186, border_color);
    for (int j = 1; j < width - 1; j++) {
      print_char(start_row + i, start_col + j, ' ', 0x70);
    }
  }

  print_char(start_row + height - 1, start_col, 200, border_color);
  for (int i = 1; i < width - 1; i++) {
    print_char(start_row + height - 1, start_col + i, 205, border_color);
  }
  print_char(start_row + height - 1, start_col + width - 1, 188, border_color);
}

void draw_flower() {
  clear_screen(0x09);
  print_string_centered(8, " __  __ _ _ _          ___  ____  ", 0x0D);
  print_string_centered(9, "|  \\/  (_) | | __ _   / _ \\/ ___| ", 0x0D);
  print_string_centered(10, "| |\\/| | | | |/ _` | | | | \\___ \\ ", 0x0D);
  print_string_centered(11, "| |  | | | | | (_| | | |_| |___) |", 0x0E);
  print_string_centered(12, "|_|  |_|_|_|_|\\__,_|  \\___/|____/ ", 0x0D);

  print_string_centered(14, "(Micro Integrated Low-Level Application OS)",
                        0x0A);
  print_string_centered(15, "An Free an open source OS.", 0x0A);
  print_string_centered(16, "by", 0x0A);
  print_string_centered(19, "FloriDevs", 0x0F);
}

// Modified to handle mouse internally
extern "C" uint8_t get_keyboard_input_nonblock() {
  uint8_t status = inb(0x64);
  if (status & 0x01) {
    uint8_t data = inb(0x60);
    if (status & 0x20) {
      handle_mouse_byte(data);
      return 0;
    } else {
      return data;
    }
  }
  return 0;
}

uint8_t get_keyboard_input() {
  while (true) {
    uint8_t status = inb(0x64);
    if (status & 0x01) {
      uint8_t data = inb(0x60);
      if (status & 0x20) {
        handle_mouse_byte(data);
        return 0;
      } else {
        return data;
      }
    }
  }
}

// ============================================================================
// SETTINGS
// ============================================================================

// Tastaturlayouts
// Tastaturlayouts
const char scancode_map_us[] = {
    0,   0,   '1', '2', '3', '4', '5', '6', '7', '8', '9',  '0', '-', '=',  0,
    0,   'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', 'o', 'p',  '[', ']', 0,    0,
    'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', '\'', '`', 0,   '\\', 'z',
    'x', 'c', 'v', 'b', 'n', 'm', ',', '.', '/', 0,   0,    0,   ' '};
const char scancode_map_us_shift[] = {
    0,   0,   '!', '@', '#', '$', '%', '^', '&', '*', '(', ')', '_', '+', 0,
    0,   'Q', 'W', 'E', 'R', 'T', 'Y', 'U', 'I', 'O', 'P', '{', '}', 0,   0,
    'A', 'S', 'D', 'F', 'G', 'H', 'J', 'K', 'L', ':', '"', '~', 0,   '|', 'Z',
    'X', 'C', 'V', 'B', 'N', 'M', '<', '>', '?', 0,   0,   0,   ' '};
const char scancode_map_de[] = {
    0,   0,   '1', '2',        '3',        '4', '5', '6', '7',
    '8', '9', '0', (char)0xE1, 0x27,       0,   0,   'q', 'w',
    'e', 'r', 't', 'z',        'u',        'i', 'o', 'p', (char)0x81,
    '+', 0,   0,   'a',        's',        'd', 'f', 'g', 'h',
    'j', 'k', 'l', (char)0x94, (char)0x84, '^', 0,   '#', 'y',
    'x', 'c', 'v', 'b',        'n',        'm', ',', '.', '-',
    0,   0,   0,   ' '};
const char scancode_map_de_shift[] = {
    0,   0,   '!', '"',        0x15,       '$',        '%', '&',  '/',
    '(', ')', '=', '?',        '`',        0,          0,   'Q',  'W',
    'E', 'R', 'T', 'Z',        'U',        'I',        'O', 'P',  (char)0x9A,
    '*', 0,   0,   'A',        'S',        'D',        'F', 'G',  'H',
    'J', 'K', 'L', (char)0x99, (char)0x8E, (char)0xF8, 0,   '\'', 'Y',
    'X', 'C', 'V', 'B',        'N',        'M',        ';', ':',  '_',
    0,   0,   0,   ' '};
const char scancode_map_fr[] = {
    0,          0,   '&',        (char)0xE9, '"', '\'', '(', '-',
    (char)0xE8, '_', (char)0xE7, (char)0xE0, ')', '=',  0,   0,
    'a',        'z', 'e',        'r',        't', 'y',  'u', 'i',
    'o',        'p', '^',        '$',        0,   0,    'q', 's',
    'd',        'f', 'g',        'h',        'j', 'k',  'l', 'm',
    (char)0xF9, '*', 0,          '\\',       'w', 'x',  'c', 'v',
    'b',        'n', ',',        ';',        ':', '!',  0,   0,
    0,          ' '};
const char scancode_map_fr_shift[] = {
    0,          0,   '1', '2',  '3', '4',        '5', '6', '7',
    '8',        '9', '0', '\0', '+', 0,          0,   'A', 'Z',
    'E',        'R', 'T', 'Y',  'U', 'I',        'O', 'P', (char)0xA8,
    (char)0xA3, 0,   0,   'Q',  'S', 'D',        'F', 'G', 'H',
    'J',        'K', 'L', 'M',  '%', (char)0xB5, 0,   '|', 'W',
    'X',        'C', 'V', 'B',  'N', '?',        '.', '/', (char)0xA7,
    0,          0,   0,   ' '};

const char *current_scancode_map = scancode_map_us;
const char *current_scancode_map_shift = scancode_map_us_shift;

char scancode_to_ascii(uint8_t scancode, bool shift) {
  if (scancode < 58) {
    return shift ? current_scancode_map_shift[scancode]
                 : current_scancode_map[scancode];
  }
  return 0;
}

// Forward declarations
void milla_ide(const char *filename);
void doc_editor(const char *filename);
void text_editor(const char *filename);
extern "C" void start_graphical_shell();

// ============================================================================
// SHELL FILESYSTEM WRAPPERS (extern C for shell.cpp)
// ============================================================================
extern "C" int get_shell_file_count() { return file_count; }

extern "C" void get_shell_file_name(int index, char *out) {
  if (index >= 0 && index < file_count) {
    string_copy(out, file_cache[index].name);
  } else {
    out[0] = '\0';
  }
}

extern "C" uint32_t get_shell_file_size(int index) {
  if (index >= 0 && index < file_count)
    return file_cache[index].size;
  return 0;
}

extern "C" bool get_shell_file_is_dir(int index) {
  if (index >= 0 && index < file_count)
    return file_cache[index].is_directory;
  return false;
}

extern "C" void shell_refresh_files() {
  if (fs_mounted && active_disk) {
    read_directory(active_disk, root_dir_first_cluster);
  }
}

extern "C" bool shell_is_fs_mounted() { return fs_mounted; }

extern "C" char shell_scancode_to_ascii(uint8_t scancode, bool shift) {
  return scancode_to_ascii(scancode, shift);
}

extern "C" void shell_set_language(int lang) {
  if (lang == 1) {
    current_scancode_map = scancode_map_de;
    current_scancode_map_shift = scancode_map_de_shift;
  } else if (lang == 2) {
    current_scancode_map = scancode_map_fr;
    current_scancode_map_shift = scancode_map_fr_shift;
  } else {
    current_scancode_map = scancode_map_us;
    current_scancode_map_shift = scancode_map_us_shift;
  }
}

extern "C" bool shell_read_file(const char *filename, char *buffer,
                                uint32_t max_size) {
  int file_idx = find_file(filename);
  if (file_idx != -1 && fs_mounted && active_disk) {
    return read_file(active_disk, file_cache[file_idx].first_cluster, buffer,
                     max_size);
  }
  return false;
}

extern "C" bool shell_write_file(const char *filename, const char *data,
                                 uint32_t size) {
  if (fs_mounted && active_disk) {
    bool res = write_file(active_disk, filename, data, size);
    if (res)
      read_directory(active_disk, root_dir_first_cluster);
    return res;
  }
  return false;
}

extern "C" bool shell_format_disk(int disk_id) {
  ATADevice *disk = disk_id == 1 ? &ramdisk_device
                                 : (hdd_device.present ? &hdd_device : nullptr);
  if (disk) {
    return format_fat16(disk, 0, disk->size_sectors);
  }
  return false;
}

extern "C" bool shell_mount_disk(int disk_id) {
  ATADevice *disk = disk_id == 1 ? &ramdisk_device
                                 : (hdd_device.present ? &hdd_device : nullptr);
  if (disk) {
    if (mount_fat16(disk, 0)) {
      active_disk = disk;
      read_directory(active_disk, root_dir_first_cluster);
      return true;
    }
    if (disk == &hdd_device && ata_read_sector(disk, 0, sector_buffer)) {
      MBR *mbr = (MBR *)sector_buffer;
      for (int i = 0; i < 4; i++) {
        if (mbr->partitions[i].total_sectors > 0) {
          if (mount_fat16(disk, mbr->partitions[i].start_lba)) {
            active_disk = disk;
            read_directory(active_disk, root_dir_first_cluster);
            return true;
          }
        }
      }
    }
  }
  return false;
}

extern "C" void shell_unmount_disk() {
  fs_mounted = false;
  file_count = 0;
}

extern "C" int shell_get_active_disk() {
  if (active_disk == &ramdisk_device)
    return 1;
  if (active_disk == &hdd_device)
    return 2;
  return 0;
}

extern "C" bool shell_is_hdd_present() { return hdd_device.present; }

// ============================================================================
// SIMULIERTER C++ PROGRAMM-LADER
// ============================================================================
void run_cpp_program(const char *filename) {
  clear_screen(0x00);
  draw_window(5, 10, 15, 60, " C++ Program Runner ", 0x0A);
  print_string(7, 12, "Executing program: ", 0x70);
  print_string(7, 31, filename, 0x70);

  print_string(9, 12, "---------------------------------------------", 0x70);
  print_string(10, 12, "Output:", 0x70);
  print_string(12, 12, "Hello, C++!", 0x0F);
  print_string(14, 12, "Program finished with exit code 0.", 0x70);
  print_string(16, 12, "---------------------------------------------", 0x70);

  print_string_centered(22, "Press any key to continue...", 0x0E);
  get_keyboard_input();
}

// ============================================================================
// DISK MANAGEMENT TOOL (ENTFERNT)
// ============================================================================
// (Funktion gelöscht)

// ============================================================================
// DATEIMANAGER
// ============================================================================

void file_manager() {
  clear_screen(0x03);

  for (int i = 0; i < 80; i++)
    print_char(0, i, ' ', 0x1F);
  print_string(0, 2, "File Manager - FAT16", 0x1E);
  print_string(0, 50, "F3=Switch Drive ESC=Exit", 0x1F); // Geändert

  draw_window(2, 5, 21, 70, " Drives & Files ", 0x0B);

  print_string(3, 8, "Active Drive:", 0x70);

  // **GEÄNDERT: Nur noch MRD0-Logik**
  char disk_info[50];
  if (active_disk == &ramdisk_device) {
    string_copy(disk_info, "[MRD0] RAM Disk - ");
  } else if (active_disk == &hdd_device) {
    string_copy(disk_info, "[HDD0] Hard Disk - ");
  } else {
    string_copy(disk_info, "[---] - ");
  }

  if (active_disk && fs_mounted) {
    int pos = string_length(disk_info);
    string_copy(disk_info + pos, "FAT16 (");
    pos = string_length(disk_info);

    // KORREKTUR: Robuste Größenberechnung (zeigt KB, da < 1 MB)
    uint32_t size_kb = (active_disk->size_sectors * 512) / 1024;
    char temp[20];
    int temp_len = 0;
    if (size_kb == 0) {
      temp[temp_len++] = '0';
    } else {
      uint32_t n = size_kb;
      // Zahlen rückwärts in temp speichern
      while (n > 0 && temp_len < 19) {
        temp[temp_len++] = '0' + (n % 10);
        n /= 10;
      }
    }
    // Zahlen in korrekter Reihenfolge in disk_info schreiben
    for (int i = temp_len - 1; i >= 0; i--) {
      disk_info[pos++] = temp[i];
    }

    disk_info[pos++] = ' ';
    disk_info[pos++] = 'K'; // Geändert auf KB
    disk_info[pos++] = 'B';
    disk_info[pos++] = ')';
    disk_info[pos] = '\0';

  } else if (active_disk) {
    string_copy(disk_info + string_length(disk_info),
                "Disk present, not mounted");
  } else {
    string_copy(disk_info + string_length(disk_info), "No disk active");
  }
  print_string(4, 8, disk_info, 0x70);

  print_string(7, 8, "Filename", 0x70);
  print_string(7, 30, "Size", 0x70);
  print_string(7, 45, "Type", 0x70);
  for (int i = 0; i < 68; i++)
    print_char(8, 6 + i, 196, 0x70);

  int selected = 0;
  bool running = true;

  while (running) {
    // Leere den Dateibereich, bevor er neu gezeichnet wird
    for (int i = 0; i < 12; i++) {
      print_string(9 + i, 8,
                   "                                                  ", 0x70);
    }

    if (fs_mounted) {
      for (int i = 0; i < file_count && i < 12; i++) {
        uint16_t color = (i == selected) ? 0x07 : 0x70;

        print_string(9 + i, 8, file_cache[i].name, color);

        char size_str[10] = "        ";
        int size = file_cache[i].size;
        int pos = 7;
        if (size == 0) {
          size_str[pos--] = '0';
        } else {
          while (size > 0 && pos >= 0) {
            size_str[pos--] = '0' + (size % 10);
            size /= 10;
          }
        }
        print_string(9 + i, 30, size_str, color);
        print_string(9 + i, 45, file_cache[i].is_directory ? "DIR" : "FILE",
                     color);
      }
    } else {
      print_string(10, 8, "No filesystem mounted.", 0x70);
    }

    for (int i = 0; i < 80; i++)
      print_char(24, i, ' ', 0x70);
    print_string(24, 2, "UP/DOWN ENTER=Open ESC=Exit", 0x70); // Geändert

    uint8_t scancode = get_keyboard_input();

    if (scancode == 0x01) {
      running = false;
    } else if (scancode == 0x3D) { // F3 - Switch Drive
      if (active_disk == &ramdisk_device && hdd_device.present) {
        active_disk = &hdd_device;
        // Auto-mount if needed
        if (!mount_fat16(active_disk, 0)) {
          // Try MBR partitions
          if (ata_read_sector(active_disk, 0, sector_buffer)) {
            if (sector_buffer[510] == 0x55 && sector_buffer[511] == 0xAA) {
              MBR *mbr = (MBR *)sector_buffer;
              for (int i = 0; i < 4; i++) {
                if (mbr->partitions[i].total_sectors > 0) {
                  if (mount_fat16(active_disk, mbr->partitions[i].start_lba))
                    break;
                }
              }
            }
          }
        }
      } else if (active_disk == &hdd_device) {
        active_disk = &ramdisk_device;
        mount_fat16(active_disk, 0); // Re-mount RAM disk just in case
      }
      // Reload Dir
      if (active_disk)
        read_directory(active_disk, root_dir_first_cluster);
      selected = 0; // Reset scroll

      // Redraw Header
      clear_screen(0x03);
      for (int i = 0; i < 80; i++)
        print_char(0, i, ' ', 0x1F);
      print_string(0, 2, "File Manager - FAT16", 0x1E);
      print_string(0, 50, "F3=Switch Drive ESC=Exit", 0x1F);
      draw_window(2, 5, 21, 70, " Drives & Files ", 0x0B);
      print_string(3, 8, "Active Drive:", 0x70);

      // Update Disk Info String
      if (active_disk == &ramdisk_device) {
        string_copy(disk_info, "[MRD0] RAM Disk - ");
      } else if (active_disk == &hdd_device) {
        string_copy(disk_info, "[HDD0] Hard Disk - ");
      } else {
        string_copy(disk_info, "[---] - ");
      }
      if (active_disk && fs_mounted) {
        int pos = string_length(disk_info);
        string_copy(disk_info + pos, "FAT16 (");
        pos = string_length(disk_info);
        uint32_t size_kb = (active_disk->size_sectors * 512) / 1024;
        // ... (Simple size append reused or simplified just print "Ready")
        string_copy(disk_info + pos, "Ready)");
      } else {
        string_copy(disk_info + string_length(disk_info), "No FS / Error");
      }
      print_string(4, 8, disk_info, 0x70);

      print_string(7, 8, "Filename", 0x70);
      print_string(7, 30, "Size", 0x70);
      print_string(7, 45, "Type", 0x70);
      for (int i = 0; i < 68; i++)
        print_char(8, 6 + i, 196, 0x70);

    } else if (scancode == 0x48 && selected > 0) {
      selected--;
    } else if (scancode == 0x50 && selected < file_count - 1) {
      selected++;
    } else if (scancode == 0x1C && file_count > 0 && active_disk &&
               fs_mounted) { // ENTER
      const char *ext = get_filename_ext(file_cache[selected].name);
      if (string_compare(ext, "TXT")) {
        text_editor(file_cache[selected].name);
        running = false;
      } else if (string_compare(ext, "MD")) {
        doc_editor(file_cache[selected].name);
        running = false;
      } else if (string_compare(ext, "MC")) {
        milla_ide(file_cache[selected].name);
        running = false;
      } else if (string_compare(ext, "CPP")) {
        run_cpp_program(file_cache[selected].name);
        // Redraw file manager
        clear_screen(0x03);
        for (int i = 0; i < 80; i++)
          print_char(0, i, ' ', 0x1F);
        print_string(0, 2, "File Manager - FAT16", 0x1E);
        print_string(0, 50, "ESC=Exit", 0x1F);
        draw_window(2, 5, 21, 70, " Drives & Files ", 0x0B);
        print_string(3, 8, "Active Drive:", 0x70);
        print_string(4, 8, disk_info, 0x70);
        print_string(7, 8, "Filename", 0x70);
        print_string(7, 30, "Size", 0x70);
        print_string(7, 45, "Type", 0x70);
        for (int i = 0; i < 68; i++)
          print_char(8, 6 + i, 196, 0x70);
      }
    }
  }
}

// ============================================================================
// TEXTEDITOR
// ============================================================================

#define EDITOR_BUFFER_SIZE 8192

char editor_buffer[EDITOR_BUFFER_SIZE];

void text_editor(const char *filename) {

  char title[40] = "Text Editor - ";
  int fn_len = string_length(filename);
  for (int i = 0; i < fn_len && i < 25; i++) {
    title[14 + i] = filename[i];
  }
  title[14 + fn_len] = '\0';

  for (int i = 0; i < 80; i++)
    print_char(0, i, ' ', 0x1F);
  print_string(0, 2, title, 0x1E);
  print_string(0, 45, "F1=Save F2=Reload ESC=Exit", 0x1F);

  // Buffer leeren (mit Leerzeichen füllen, wie im Original)
  for (int i = 0; i < EDITOR_BUFFER_SIZE; i++)
    editor_buffer[i] = ' ';
  int buffer_pos = 0;

  int file_idx = find_file(filename);
  if (file_idx != -1 && fs_mounted && active_disk) {
    read_file(active_disk, file_cache[file_idx].first_cluster, editor_buffer,
              file_cache[file_idx].size < EDITOR_BUFFER_SIZE
                  ? file_cache[file_idx].size
                  : EDITOR_BUFFER_SIZE);
    buffer_pos = file_cache[file_idx].size;
  } else {
    // Datei existiert nicht (oder ist neu), buffer_pos bleibt 0
    buffer_pos = 0;
  }

  // Fülle den Rest des Puffers mit Leerzeichen (read_file nullterminiert,
  // aber der Editor erwartet Leerzeichen zum Rendern)
  for (int i = buffer_pos; i < EDITOR_BUFFER_SIZE; i++)
    editor_buffer[i] = ' ';

  int cursor_row = 1;
  int cursor_col = 0;
  bool shift_pressed = false;
  bool running = true;

  while (running) {
    for (int row = 1; row < 24; row++) {
      for (int col = 0; col < 80; col++) {
        int pos = (row - 1) * 80 + col;
        if (pos < EDITOR_BUFFER_SIZE) {
          print_char(row, col,
                     editor_buffer[pos] == '\n' ? ' ' : editor_buffer[pos],
                     0x0F);
        }
      }
    }

    print_char(cursor_row, cursor_col, 219, 0x0E);

    for (int i = 0; i < 80; i++)
      print_char(24, i, ' ', 0x70);
    char status[40];
    string_copy(status, "Row: ");
    status[5] = '0' + (cursor_row / 10);
    status[6] = '0' + (cursor_row % 10);
    status[7] = ' ';
    status[8] = 'C';
    status[9] = 'o';
    status[10] = 'l';
    status[11] = ':';
    status[12] = ' ';
    status[13] = '0' + (cursor_col / 10);
    status[14] = '0' + (cursor_col % 10);
    status[15] = '\0';
    print_string(24, 2, status, 0x70);

    uint8_t scancode = get_keyboard_input();

    if (scancode == 0x01) {
      running = false;
    } else if (scancode == 0x3B) { // F1 - Save
      if (fs_mounted && active_disk) {

        // KORREKTUR: Berechne die tatsächliche Größe (ignoriere nachfolgende
        // Leerzeichen/Nulls)
        int actual_size = EDITOR_BUFFER_SIZE - 1;
        while (actual_size >= 0 && (editor_buffer[actual_size] == ' ' ||
                                    editor_buffer[actual_size] == '\0' ||
                                    editor_buffer[actual_size] == '\n')) {
          actual_size--;
        }
        buffer_pos = actual_size + 1; // Größe ist Index + 1

        // TODO: Datei löschen/überschreiben, falls sie existiert
        // (Aktuelle Implementierung fügt nur hinzu)
        write_file(active_disk, filename, editor_buffer, buffer_pos);
        read_directory(active_disk, root_dir_first_cluster);
        print_string(24, 30, "File saved to disk!", 0x72);
        delay(10);
      }
    } else if (scancode == 0x3C) {    // F2 - Reload
      file_idx = find_file(filename); // Index neu finden
      if (file_idx != -1 && fs_mounted && active_disk) {
        for (int i = 0; i < EDITOR_BUFFER_SIZE; i++)
          editor_buffer[i] = ' ';
        read_file(active_disk, file_cache[file_idx].first_cluster,
                  editor_buffer,
                  file_cache[file_idx].size < EDITOR_BUFFER_SIZE
                      ? file_cache[file_idx].size
                      : EDITOR_BUFFER_SIZE);
        buffer_pos = file_cache[file_idx].size;
        // Fülle Rest mit Leerzeichen
        for (int i = buffer_pos; i < EDITOR_BUFFER_SIZE; i++)
          editor_buffer[i] = ' ';

        print_string(24, 30, "File reloaded!", 0x72);
        delay(10);
      }
    } else if (scancode == 0x2A || scancode == 0x36) {
      shift_pressed = true;
    } else if (scancode == 0xAA || scancode == 0xB6) {
      shift_pressed = false;
    } else if (scancode == 0x48 && cursor_row > 1) {
      cursor_row--;
    } else if (scancode == 0x50 && cursor_row < 23) {
      cursor_row++;
    } else if (scancode == 0x4B && cursor_col > 0) {
      cursor_col--;
    } else if (scancode == 0x4D && cursor_col < 79) {
      cursor_col++;
    } else if (scancode == 0x0E) { // Backspace
      int pos = (cursor_row - 1) * 80 + cursor_col;
      if (pos > 0) {
        // Bewege Cursor
        if (cursor_col > 0) {
          cursor_col--;
        } else if (cursor_row > 1) {
          cursor_row--;
          cursor_col = 79;
        }

        // Aktualisiere Puffer (Zeichen löschen und Rest nachrücken)
        int new_pos = (cursor_row - 1) * 80 + cursor_col;
        for (int i = new_pos; i < EDITOR_BUFFER_SIZE - 1; ++i) {
          editor_buffer[i] = editor_buffer[i + 1];
        }
        editor_buffer[EDITOR_BUFFER_SIZE - 1] = ' '; // Letztes Feld aufräumen
      }
    } else if (scancode == 0x1C) { // Enter
      if (cursor_row < 23) {
        cursor_row++;
        cursor_col = 0;
      }
    } else {
      char ch = scancode_to_ascii(scancode, shift_pressed);
      if (ch != 0) {
        int pos = (cursor_row - 1) * 80 + cursor_col;
        if (pos < EDITOR_BUFFER_SIZE - 1) {
          editor_buffer[pos] = ch;
          if (pos >= buffer_pos)
            buffer_pos = pos + 1;

          if (cursor_col < 79) {
            cursor_col++;
          } else if (cursor_row < 23) {
            cursor_row++;
            cursor_col = 0;
          }
        }
      }
    }
  }
}

// ============================================================================
// TASCHENRECHNER
// ============================================================================

void calculator() {
  clear_screen(0x03);

  for (int i = 0; i < 80; i++)
    print_char(0, i, ' ', 0x1F);
  print_string(0, 2, "Calculator", 0x1E);
  print_string(0, 60, "ESC=Exit", 0x1F);

  draw_window(3, 20, 18, 40, " Calculator ", 0x0B);

  char display[20] = "0";
  int display_len = 1;
  long num1 = 0;
  long num2 = 0;
  char operation = 0;
  bool new_number = true;
  bool running = true;
  bool shift_pressed = false;

  int cursor_x = 0, cursor_y = 0;

  while (running) {
    print_string(5, 22, "                                  ", 0x70);
    print_string(5, 41 - display_len, display, 0x0F);

    const char *buttons[16] = {"7", "8", "9", "/", "4", "5", "6", "*",
                               "1", "2", "3", "-", "0", "C", "=", "+"};

    for (int y = 0; y < 4; y++) {
      for (int x = 0; x < 4; x++) {
        int row = 7 + y * 3;
        int col = 23 + x * 8;
        uint16_t color = (x == cursor_x && y == cursor_y) ? 0x07 : 0x70;
        uint16_t text_color = (x == cursor_x && y == cursor_y) ? 0x0E : 0x7E;
        print_char(row, col, '[', color);
        print_string(row, col + 1, buttons[y * 4 + x], text_color);
        print_char(row, col + 1 + string_length(buttons[y * 4 + x]), ']',
                   color);
      }
    }

    for (int i = 0; i < 80; i++)
      print_char(24, i, ' ', 0x70);
    print_string(24, 2, "Arrow keys, Enter to select, ESC=Exit", 0x70);

    uint8_t scancode = get_keyboard_input();

    char ch_input = 0;

    if (scancode == 0x01) {
      running = false;
    } else if (scancode == 0x48 && cursor_y > 0) {
      cursor_y--;
    } else if (scancode == 0x50 && cursor_y < 3) {
      cursor_y++;
    } else if (scancode == 0x4B && cursor_x > 0) {
      cursor_x--;
    } else if (scancode == 0x4D && cursor_x < 3) {
      cursor_x++;
    } else if (scancode == 0x1C) {
      ch_input = buttons[cursor_y * 4 + cursor_x][0];
    } else if (scancode == 0x2A || scancode == 0x36) {
      shift_pressed = true;
    } else if (scancode == 0xAA || scancode == 0xB6) {
      shift_pressed = false;
    } else {
      ch_input = scancode_to_ascii(scancode, shift_pressed);
    }

    if (ch_input >= '0' && ch_input <= '9') {
      if (new_number) {
        display[0] = ch_input;
        display[1] = '\0';
        display_len = 1;
        new_number = false;
      } else if (display_len < 15) {
        display[display_len++] = ch_input;
        display[display_len] = '\0';
      }
    } else if (ch_input == '+' || ch_input == '-' || ch_input == '*' ||
               ch_input == '/') {
      num1 = 0;
      for (int i = 0; i < display_len; ++i)
        num1 = num1 * 10 + (display[i] - '0');
      operation = ch_input;
      new_number = true;
    } else if (ch_input == '=') {
      num2 = 0;
      for (int i = 0; i < display_len; ++i)
        num2 = num2 * 10 + (display[i] - '0');
      long result = 0;
      if (operation == '+')
        result = num1 + num2;
      else if (operation == '-')
        result = num1 - num2;
      else if (operation == '*')
        result = num1 * num2;
      else if (operation == '/' && num2 != 0)
        result = num1 / num2;
      else if (operation == '/' && num2 == 0) {
        string_copy(display, "DIV BY ZERO");
        display_len = 11;
        operation = 0;
        new_number = true;
        continue;
      } else
        result = num2;

      display_len = 0;
      if (result == 0) {
        display[0] = '0';
        display_len = 1;
      } else {
        char temp[20];
        int temp_len = 0;
        long r = result;
        bool negative = false;
        if (r < 0) {
          negative = true;
          r = -r;
        }
        while (r > 0) {
          temp[temp_len++] = '0' + (r % 10);
          r /= 10;
        }
        if (negative)
          display[display_len++] = '-';
        for (int i = temp_len - 1; i >= 0; i--)
          display[display_len++] = temp[i];
      }
      display[display_len] = '\0';
      operation = 0;
      new_number = true;
    } else if (ch_input == 'C') {
      display[0] = '0';
      display[1] = '\0';
      display_len = 1;
      num1 = 0;
      num2 = 0;
      operation = 0;
      new_number = true;
    }
  }
}

void disk_management() {
  bool running = true;
  int selected_dev = 0; // 0=RAM, 1=HDD
  while (running) {
    if (show_wallpaper)
      draw_wallpaper_text();
    else
      clear_screen(0x03);

    draw_window(5, 5, 18, 70, " Disk Management ", 0x0B);
    print_string(7, 8, "Select Device:", 0x70);

    uint16_t col0 = (selected_dev == 0) ? 0x0F : 0x07;
    uint16_t col1 = (selected_dev == 1) ? 0x0F : 0x07;
    print_string(9, 10, "1. RAM DISK (MRD0)", col0);
    print_string(11, 10, "2. HARD DISK (HDD0)", col1);

    ATADevice *dev = (selected_dev == 0) ? &ramdisk_device : &hdd_device;
    if (dev->present) {
      print_string(9, 40, "Status: Present ", 0x0A);
      // Scan for partitions
      if (ata_read_sector(dev, 0, sector_buffer)) {
        if (sector_buffer[510] == 0x55 && sector_buffer[511] == 0xAA) {
          MBR *mbr = (MBR *)sector_buffer;
          char p_str[30] = "P1: None";
          if (mbr->partitions[0].system_id != 0) {
            string_copy(p_str, "P1: FAT16 (");
            int pos = 11;
            uint32_t size_mb =
                (mbr->partitions[0].total_sectors * 512) / (1024 * 1024);
            if (size_mb == 0)
              p_str[pos++] = '0';
            else {
              if (size_mb >= 100)
                p_str[pos++] = '0' + (size_mb / 100) % 10;
              if (size_mb >= 10)
                p_str[pos++] = '0' + (size_mb / 10) % 10;
              p_str[pos++] = '0' + (size_mb % 10);
            }
            string_copy(p_str + pos, "MB)");
            print_string(11, 40, p_str, 0x0A);
          } else {
            if (sector_buffer[54] == 'F' && sector_buffer[55] == 'A')
              print_string(11, 40, "MBR: Superfloppy", 0x0E);
            else
              print_string(11, 40, "MBR: Empty/Raw  ", 0x07);
          }
        }
      }
    } else {
      print_string(9, 40, "Status: Missing ", 0x0C);
    }

    print_string(15, 8, "Actions: [F1] Format MBR  [F2] Format FAT  [F3] Mount",
                 0x70);
    print_string(16, 8, "         [F4] Use Empty Partition", 0x70);
    print_string(21, 8, "ESC: Back", 0x70);

    // Render mouse
    print_char(mouse_y, mouse_x, (char)219, 0x0E);

    uint8_t sc = get_keyboard_input();
    if (sc == 0x01)
      running = false;
    else if (sc == 0x48 || sc == 0x50)
      selected_dev = 1 - selected_dev;
    else if (sc == 0x3B) { // F1
      if (format_mbr(dev)) {
        print_string(18, 8, "MBR Formatted successfully!   ", 0x0A);
        delay(10);
      }
    } else if (sc == 0x3C) { // F2
      uint32_t offset = 0;
      uint32_t size = dev->size_sectors;
      ata_read_sector(dev, 0, sector_buffer);
      MBR *mbr = (MBR *)sector_buffer;
      if (mbr->partitions[0].system_id != 0) {
        offset = mbr->partitions[0].start_lba;
        size = mbr->partitions[0].total_sectors;
      }
      if (format_fat16(dev, offset, size)) {
        print_string(18, 8, "FAT16 Formatted successfully! ", 0x0A);
        delay(10);
        if (mount_fat16(dev, offset)) {
          active_disk = dev;
          read_directory(active_disk, root_dir_first_cluster);
        }
      }
    } else if (sc == 0x3D) { // F3
      uint32_t offset = 0;
      ata_read_sector(dev, 0, sector_buffer);
      MBR *mbr = (MBR *)sector_buffer;
      if (mbr->partitions[0].system_id != 0)
        offset = mbr->partitions[0].start_lba;
      if (mount_fat16(dev, offset)) {
        active_disk = dev;
        read_directory(active_disk, root_dir_first_cluster);
        print_string(18, 8, "Mounted successfully!         ", 0x0A);
        delay(10);
      } else {
        print_string(18, 8, "Mount failed! No FAT found.   ", 0x0C);
        delay(10);
      }
    } else if (sc == 0x3E) { // F4 - Use Empty
      ata_read_sector(dev, 0, sector_buffer);
      MBR *mbr = (MBR *)sector_buffer;
      bool found = false;
      for (int i = 0; i < 4; i++) {
        if (mbr->partitions[i].total_sectors > 0) {
          if (!mount_fat16(dev, mbr->partitions[i].start_lba)) {
            if (format_fat16(dev, mbr->partitions[i].start_lba,
                             mbr->partitions[i].total_sectors)) {
              print_string(18, 8, "Formatted empty partition!    ", 0x0E);
              mount_fat16(dev, mbr->partitions[i].start_lba);
              active_disk = dev;
              found = true;
              delay(10);
              break;
            }
          } else {
            active_disk = dev;
            found = true;
            print_string(18, 8, "Found and used existing FAT!  ", 0x0A);
            delay(10);
            break;
          }
        }
      }
      if (!found) {
        print_string(18, 8, "No usable partition found!    ", 0x0C);
        delay(10);
      }
    }
  }
}

void settings() {
  bool running = true;
  int selected = 0;

  // MERGED SETTINGS MENU
  while (running) {
    // Redraw Background
    if (show_wallpaper) {
      // Redraw underlying if transparent...
      draw_wallpaper_text(); // Simple redraw
    } else {
      clear_screen(0x03);
    }

    // Draw Window
    draw_window(5, 20, 18, 40, " Settings ", 0x0D);

    const char *opts[] = {"1. Toggle Wallpaper", "2. Keyboard Layout",
                          "3. Disk Management", "4. Exit"};

    // Draw Options
    for (int i = 0; i < 4; i++) {
      uint16_t col = (selected == i) ? 0x0F : 0x07;
      print_string(8 + i * 2, 22, opts[i], col);

      // Value next to option
      if (i == 0) {
        if (show_wallpaper)
          print_string(8, 50, "[ON] ", 0x0A);
        else
          print_string(8, 50, "[OFF]", 0x0C);
      } else if (i == 1) {
        if (current_scancode_map == scancode_map_de)
          print_string(10, 50, "[DE]", 0x0E);
        else
          print_string(10, 50, "[US]", 0x0E);
      } else if (i == 2) {
        if (active_disk == &ramdisk_device)
          print_string(12, 50, "[RAM]", 0x0E);
        else if (active_disk == &hdd_device)
          print_string(12, 50, "[HDD]", 0x0E);
      }
    }

    // MOUSE CURSOR
    print_char(mouse_y, mouse_x, (char)219, 0x0E);

    uint8_t sc = get_keyboard_input();

    if (sc == 0)
      continue;

    if (sc == 0x01) { // ESC
      running = false;
    } else if (sc == 0x1C) { // ENTER
      if (selected == 0) {
        show_wallpaper = !show_wallpaper;
      } else if (selected == 1) {
        if (current_scancode_map == scancode_map_de) {
          current_scancode_map = scancode_map_us;
          current_scancode_map_shift = scancode_map_us_shift;
        } else {
          current_scancode_map = scancode_map_de;
          current_scancode_map_shift = scancode_map_de_shift;
        }
      } else if (selected == 2) {
        disk_management();
      } else if (selected == 3) {
        running = false;
      }
    } else if (sc == 0x48) { // Up
      if (selected > 0)
        selected--;
    } else if (sc == 0x50) { // Down
      if (selected < 3)
        selected++;
    }
  }
}

// ============================================================================
// HILFSFUNKTION FÜR TEXTEINGABE (NEU)
// ============================================================================
void get_string_input(int row, int col, int width, const char *prompt,
                      char *buffer, int max_len) {
  // Zeichne Prompt und Box
  draw_window(row, col, 3, width, prompt, 0x0E);

  int pos = string_length(buffer);
  bool running = true;
  bool shift_pressed = false;

  while (running) {
    // Zeichne aktuellen Buffer-Inhalt neu
    for (int i = 0; i < width - 2; i++) {
      char c = (i < pos) ? buffer[i] : ' ';
      print_char(row + 1, col + 1 + i, c, 0x70);
    }
    // Zeichne Cursor
    print_char(row + 1, col + 1 + pos, 219, 0x0F);

    uint8_t scancode = get_keyboard_input();

    // Verstecke Cursor
    print_char(row + 1, col + 1 + pos,
               (pos < string_length(buffer)) ? buffer[pos] : ' ', 0x70);

    if (scancode == 0x01) { // ESC
      buffer[0] = '\0';     // Eingabe abbrechen
      running = false;
    } else if (scancode == 0x1C) { // ENTER
      running = false;
    } else if (scancode == 0x0E) { // Backspace
      if (pos > 0) {
        pos--;
        buffer[pos] = '\0';
      }
    } else if (scancode == 0x2A || scancode == 0x36) {
      shift_pressed = true;
    } else if (scancode == 0xAA || scancode == 0xB6) {
      shift_pressed = false;
    } else {
      char ch = scancode_to_ascii(scancode, shift_pressed);
      // Erlaube nur gültige Dateinamenzeichen (grobe Prüfung)
      bool valid_char = (ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z') ||
                        (ch >= '0' && ch <= '9') || ch == '.' || ch == '_';

      if (ch != 0 && valid_char && pos < max_len && pos < width - 3) {
        // Konvertiere zu Großbuchstaben (FAT16-Standard NICHT ERZWINGEN hier
        // für URL) if (ch >= 'a' && ch <= 'z') ch -= 32;

        buffer[pos] = ch;
        pos++;
        buffer[pos] = '\0';
      }
    }
  }

  // Bereinige den Eingabebereich (stelle Menühintergrund wieder her)
  // (Wird durch das Neuzeichnen des Menüs in main_menu erledigt)
}

// ============================================================================
// MILLA LANG
// ============================================================================

struct MillaVar {
  char name[32];
  char value[64];
  bool in_use;
};

MillaVar milla_vars[20];
char milla_log[20][80]; // Console history
int milla_log_count = 0;

// Random Number Generator (LCG)
unsigned long milla_rand_seed = 123456789;
int milla_rand(int min, int max) {
  milla_rand_seed = milla_rand_seed * 1103515245 + 12345;
  unsigned int r = (unsigned int)(milla_rand_seed / 65536) % 32768;
  if (min > max) {
    int t = min;
    min = max;
    max = t;
  }
  return min + (r % (max - min + 1));
}

// Helper: Parse integer
int milla_atoi(const char *s) {
  int res = 0;
  int sign = 1;
  int i = 0;
  if (s[0] == '-') {
    sign = -1;
    i++;
  }
  for (; s[i] != '\0'; ++i) {
    if (s[i] >= '0' && s[i] <= '9')
      res = res * 10 + s[i] - '0';
  }
  return sign * res;
}

// Helper: Int to String
void milla_itoa(int n, char *s) {
  int i = 0, sign = n;
  if (n < 0)
    n = -n;
  do {
    s[i++] = n % 10 + '0';
  } while ((n /= 10) > 0);
  if (sign < 0)
    s[i++] = '-';
  s[i] = '\0';
  // Reverse
  for (int j = 0, k = i - 1; j < k; j++, k--) {
    char t = s[j];
    s[j] = s[k];
    s[k] = t;
  }
}

// Add line to log
void milla_print(const char *msg) {
  if (milla_log_count < 20) {
    string_copy(milla_log[milla_log_count], msg);
    milla_log_count++;
  } else {
    // Shift up
    for (int i = 0; i < 19; i++)
      string_copy(milla_log[i], milla_log[i + 1]);
    string_copy(milla_log[19], msg);
  }
}

// Evaluate command
void milla_eval(const char *cmd) {
  char buffer[80];
  string_copy(buffer, cmd);

  // Tokenize (simple space split)
  char arg1[32] = "";
  char arg2[32] = "";
  char arg3[32] = ""; // Extra arg
  char command[32] = "";

  int space1 = -1, space2 = -1, space3 = -1;
  int len = string_length(buffer);

  // Find spaces
  for (int i = 0; i < len; i++) {
    if (buffer[i] == ' ') {
      if (space1 == -1)
        space1 = i;
      else if (space2 == -1)
        space2 = i;
      else if (space3 == -1)
        space3 = i;
    }
  }

  // Extract command
  int cmd_len = (space1 == -1) ? len : space1;
  for (int i = 0; i < cmd_len && i < 31; i++)
    command[i] = buffer[i];
  command[cmd_len] = '\0';

  // Extract Arg1
  if (space1 != -1) {
    int start = space1 + 1;
    int end = (space2 == -1) ? len : space2;
    int k = 0;
    for (int i = start; i < end && k < 31; i++)
      arg1[k++] = buffer[i];
    arg1[k] = '\0';
  }

  // Extract Arg2
  if (space2 != -1) {
    int start = space2 + 1;
    int end = (space3 == -1) ? len : space3;
    int k = 0;
    for (int i = start; i < end && k < 31; i++)
      arg2[k++] = buffer[i];
    arg2[k] = '\0';
  }

  // Extract Arg3
  if (space3 != -1) {
    int start = space3 + 1;
    int end = len;
    int k = 0;
    for (int i = start; i < end && k < 31; i++)
      arg3[k++] = buffer[i];
    arg3[k] = '\0';
  }

  // --- COMMANDS ---

  if (string_compare(command, "PRINT")) {
    if (arg1[0] == '"') {
      // String literal: Remove quotes (simple)
      char output[64];
      int k = 0;
      for (int i = 1; arg1[i] != '\0' && arg1[i] != '"'; i++)
        output[k++] = arg1[i];
      output[k] = '\0';
      milla_print(output);
    } else {
      // Variable lookup
      bool found = false;
      for (int i = 0; i < 20; i++) {
        if (milla_vars[i].in_use && string_compare(milla_vars[i].name, arg1)) {
          milla_print(milla_vars[i].value);
          found = true;
          break;
        }
      }
      if (!found)
        milla_print("Error: Var not found");
    }

  } else if (string_compare(command, "VAR")) {
    // VAR x = val
    if (string_compare(arg2, "=")) {
      // Save variable
      bool found = false;
      // Update existing
      for (int i = 0; i < 20; i++) {
        if (milla_vars[i].in_use && string_compare(milla_vars[i].name, arg1)) {
          string_copy(milla_vars[i].value, arg3);
          found = true;
          milla_print("Var updated.");
          break;
        }
      }
      // Create new
      if (!found) {
        for (int i = 0; i < 20; i++) {
          if (!milla_vars[i].in_use) {
            string_copy(milla_vars[i].name, arg1);
            string_copy(milla_vars[i].value, arg3);
            milla_vars[i].in_use = true;
            milla_print("Var set.");
            break;
          }
        }
      }
    } else {
      milla_print("Syntax: VAR name = value");
    }

  } else if (string_compare(command, "RANDOM")) {
    // RANDOM min max
    int min = milla_atoi(arg1);
    int max = milla_atoi(arg2);
    int r = milla_rand(min, max);
    char r_str[32];
    milla_itoa(r, r_str);
    char msg[60] = "Random: ";
    int l = 8;
    for (int i = 0; r_str[i] != 0; i++)
      msg[l++] = r_str[i];
    msg[l] = '\0';
    milla_print(msg);

  } else if (string_compare(command, "CALC")) {
    // CALC 1 + 1 (arg1 op arg2)
    int v1 = 0, v2 = 0;

    // Parse v1
    if (arg1[0] >= '0' && arg1[0] <= '9')
      v1 = milla_atoi(arg1);
    else {
      for (int i = 0; i < 20; i++)
        if (milla_vars[i].in_use && string_compare(milla_vars[i].name, arg1))
          v1 = milla_atoi(milla_vars[i].value);
    }

    char op = arg2[0];
    if (arg3[0] >= '0' && arg3[0] <= '9')
      v2 = milla_atoi(arg3);
    else {
      for (int i = 0; i < 20; i++)
        if (milla_vars[i].in_use && string_compare(milla_vars[i].name, arg3))
          v2 = milla_atoi(milla_vars[i].value);
    }

    int res = 0;
    if (op == '+')
      res = v1 + v2;
    else if (op == '-')
      res = v1 - v2;
    else if (op == '*')
      res = v1 * v2;
    else if (op == '/') {
      if (v2 != 0)
        res = v1 / v2;
    }

    char r_str[32];
    milla_itoa(res, r_str);
    char msg[60] = "Result: ";
    int l = 8;
    for (int i = 0; r_str[i] != 0; i++)
      msg[l++] = r_str[i];
    msg[l] = '\0';
    milla_print(msg);

  } else if (string_compare(command, "CLS")) {
    milla_log_count = 0;
    milla_print("Cleared.");
  } else if (string_compare(command, "HELP")) {
    milla_print("Cmds: PRINT, VAR, RANDOM, CALC");
  } else {
    if (string_length(command) > 0)
      milla_print("Unknown Command");
  }
}

// Run a full script buffer
void milla_run_script(const char *script) {
  milla_print("--- Running Script ---");
  char line_buffer[80];
  int line_pos = 0;

  for (int i = 0; script[i] != '\0'; i++) {
    char c = script[i];
    if (c == '\n') {
      line_buffer[line_pos] = '\0';
      if (line_pos > 0)
        milla_eval(line_buffer);
      line_pos = 0;
    } else {
      if (line_pos < 79)
        line_buffer[line_pos++] = c;
    }
  }
  // Last line
  if (line_pos > 0) {
    line_buffer[line_pos] = '\0';
    milla_eval(line_buffer);
  }
  milla_print("--- Finished ---");
}

void milla_lang() {
  clear_screen(0x0F);
  milla_log_count = 0; // Reset log on start
  milla_print("Welcome to Milla Lang v1.0");
  milla_print("Type HELP for commands. ESC to exit.");

  char input[80] = "";
  int input_len = 0;
  bool running = true;
  bool shift = false;

  while (running) {
    // Draw Interface
    draw_window(0, 0, 2, 80, " Milla Lang REPL ", 0x0B);

    // Draw Log
    for (int i = 0; i < 20; i++) {
      // Clear line
      for (int x = 0; x < 80; x++)
        print_char(3 + i, x, ' ', 0x0F);
      // Print log
      if (i < milla_log_count)
        print_string(3 + i, 2, milla_log[i], 0x0F);
    }

    // Draw Input Line
    for (int x = 0; x < 80; x++)
      print_char(24, x, ' ', 0x1F);
    print_string(24, 0, "> ", 0x1E);
    print_string(24, 2, input, 0x1F);
    print_char(24, 2 + input_len, 219, 0x1E); // Cursor

    // Input Handling
    uint8_t sc = get_keyboard_input();

    if (sc == 0x01) { // ESC
      running = false;
    } else if (sc == 0x1C) { // ENTER
      milla_print(input);    // Echo input
      milla_eval(input);
      input[0] = '\0';
      input_len = 0;
    } else if (sc == 0x0E) { // Backspace
      if (input_len > 0) {
        input_len--;
        input[input_len] = '\0';
      }
    } else if (sc == 0x2A || sc == 0x36) {
      shift = true;
    } else if (sc == 0xAA || sc == 0xB6) {
      shift = false;
    } else {
      char c = scancode_to_ascii(sc, shift);
      if (c != 0 && input_len < 75) {
        input[input_len++] = c;
        input[input_len] = '\0';
      }
    }
  }
}

// IDE for MillaCode
void milla_ide(const char *filename) {
  // Reusing Editor Buffer logic
  // Clear buffer first
  for (int i = 0; i < EDITOR_BUFFER_SIZE; i++)
    editor_buffer[i] = ' ';

  int file_idx = find_file(filename);
  int buffer_pos = 0;

  if (file_idx != -1 && fs_mounted && active_disk) {
    read_file(active_disk, file_cache[file_idx].first_cluster, editor_buffer,
              file_cache[file_idx].size < EDITOR_BUFFER_SIZE
                  ? file_cache[file_idx].size
                  : EDITOR_BUFFER_SIZE);
    buffer_pos = file_cache[file_idx].size;
  }

  // Fill rest with spaces
  for (int i = buffer_pos; i < EDITOR_BUFFER_SIZE; i++)
    editor_buffer[i] = ' ';

  int cursor_row = 1;
  int cursor_col = 0;
  bool shift = false;
  bool running = true;
  bool show_help = false;

  while (running) {
    // Draw Header
    draw_window(0, 0, 2, 80, " MillaCode IDE ", 0x09);
    print_string(0, 60, "F1:Help F5:Run TAB:Auto", 0x0F);
    print_string(0, 2, filename, 0x0E);

    // Draw Content (Syntax Highlighting)
    for (int row = 1; row < 24; row++) {
      for (int col = 0; col < 80; col++) {
        int pos = (row - 1) * 80 + col;
        if (pos < EDITOR_BUFFER_SIZE) {
          char c = editor_buffer[pos];
          if (c == '\n')
            c = ' ';

          uint16_t color = 0x0F;
          // Very Basic Keyword Highlighting check (slow but works for small
          // screen) Check if we are at start of a keyword? To keep it simple,
          // just highlight Uppercase words?
          if (c >= 'A' && c <= 'Z')
            color = 0x0B; // Cyan for commands

          print_char(row, col, c, color);
        }
      }
    }

    // Draw Help Overlay if active
    if (show_help) {
      draw_window(5, 10, 15, 60, " MillaCode Help ", 0x4F);
      print_string(7, 12, "PRINT \"Text\" : Show text", 0x4F);
      print_string(8, 12, "VAR x = val  : Set variable", 0x4F);
      print_string(9, 12, "CALC 1 + 1   : Calculate", 0x4F);
      print_string(10, 12, "RANDOM 1 10  : Random Num", 0x4F);
      print_string(18, 12, "Press F1 to Close", 0x4F);
    }

    // Draw Cursor
    if (!show_help)
      print_char(cursor_row, cursor_col, 219, 0x0E);

    uint8_t sc = get_keyboard_input();

    if (sc == 0x01) { // ESC
      running = false;
    } else if (sc == 0x3B) { // F1 Help
      show_help = !show_help;
      // Force redraw
      clear_screen(0x00);
    } else if (sc == 0x3F) { // F5 Run
      // Save first (auto-save for run)
      // Calculate size
      int actual_size = EDITOR_BUFFER_SIZE - 1;
      while (actual_size >= 0 && (editor_buffer[actual_size] == ' ' ||
                                  editor_buffer[actual_size] == '\0' ||
                                  editor_buffer[actual_size] == '\n')) {
        actual_size--;
      }
      write_file(active_disk, filename, editor_buffer, actual_size + 1);

      // EXECUTE
      milla_lang(); // Switch to REPL context
      milla_print("--- IDE RUN ---");

      // Need a temp buffer copy for run script because REPL uses its own loops?
      // Actually milla_run_script parses buffers
      // Create a null-terminated copy of editor buffer (run time copy)
      // Warning: Stack size.
      // We'll just pass editor_buffer directly assuming it's safeish (might
      // have spaces at end)
      char *run_buf = (char *)malloc(actual_size + 2);
      if (run_buf) {
        for (int i = 0; i <= actual_size; i++)
          run_buf[i] = editor_buffer[i];
        run_buf[actual_size + 1] = '\0';
        milla_run_script(run_buf);
        free(run_buf);
      }

      // Wait for key
      print_string(24, 0, "Press Any Key...", 0x8E);
      get_keyboard_input();
      clear_screen(0x00);                  // Clear back for IDE
    } else if (sc == 0x0F && !show_help) { // TAB - Autocomplete
      // Find word before cursor
      int p = (cursor_row - 1) * 80 + cursor_col;
      if (p > 0) {
        char prefix[10];
        int len = 0;
        int start = p - 1;
        while (start >= 0 && editor_buffer[start] != ' ' &&
               editor_buffer[start] != '\n' && len < 8) {
          start--;
        }
        start++; // Move back to first char
        // Copy prefix
        for (int i = start; i < p; i++) {
          char c = editor_buffer[i];
          if (c >= 'a' && c <= 'z')
            c -= 32; // To upper
          prefix[len++] = c;
        }
        prefix[len] = '\0';

        const char *prediction = nullptr;
        if (string_compare(prefix, "P") || string_compare(prefix, "PR"))
          prediction = "PRINT ";
        else if (string_compare(prefix, "V") || string_compare(prefix, "VA"))
          prediction = "VAR ";
        else if (string_compare(prefix, "R") || string_compare(prefix, "RA"))
          prediction = "RANDOM ";
        else if (string_compare(prefix, "C") || string_compare(prefix, "CA"))
          prediction = "CALC ";

        if (prediction) {
          // Insert prediction
          // 1. Remove typed prefix
          for (int i = 0; i < len; i++) {
            // Backspace logic locally
            cursor_col--;
            p--;
          }
          // 2. Insert full word
          int pred_len = string_length(prediction);
          for (int i = 0; i < pred_len; i++) {
            if (p < EDITOR_BUFFER_SIZE) {
              editor_buffer[p++] = prediction[i];
              cursor_col++;
            }
          }
        }
      }
    } else if (!show_help) {
      // Standard Editor Logic (Simplified copy)
      if (sc == 0x2A || sc == 0x36)
        shift = true;
      else if (sc == 0xAA || sc == 0xB6)
        shift = false;
      else if (sc == 0x48 && cursor_row > 1)
        cursor_row--;
      else if (sc == 0x50 && cursor_row < 23)
        cursor_row++;
      else if (sc == 0x4B && cursor_col > 0)
        cursor_col--;
      else if (sc == 0x4D && cursor_col < 79)
        cursor_col++;
      else if (sc == 0x0E) { // Backspace
        int pos = (cursor_row - 1) * 80 + cursor_col;
        if (pos > 0) {
          if (cursor_col > 0)
            cursor_col--;
          else if (cursor_row > 1) {
            cursor_row--;
            cursor_col = 79;
          }
          // Shift buffer
          int new_pos = (cursor_row - 1) * 80 + cursor_col;
          for (int i = new_pos; i < EDITOR_BUFFER_SIZE - 1; i++)
            editor_buffer[i] = editor_buffer[i + 1];
        }
      } else if (sc == 0x1C) { // Enter
        if (cursor_row < 23) {
          cursor_row++;
          cursor_col = 0;
        }
      } else {
        char c = scancode_to_ascii(sc, shift);
        if (c != 0) {
          int pos = (cursor_row - 1) * 80 + cursor_col;
          if (pos < EDITOR_BUFFER_SIZE) {
            editor_buffer[pos] = c;
            if (cursor_col < 79)
              cursor_col++;
            else if (cursor_row < 23) {
              cursor_row++;
              cursor_col = 0;
            }
          }
        }
      }
    }
  }
  // Save on exit? optional.
}

// DOC Editor (Markdown-like)
void doc_editor(const char *filename) {
  // Reusing Editor Buffer logic
  for (int i = 0; i < EDITOR_BUFFER_SIZE; i++)
    editor_buffer[i] = ' ';

  int file_idx = find_file(filename);
  int buffer_pos = 0;

  if (file_idx != -1 && fs_mounted && active_disk) {
    read_file(active_disk, file_cache[file_idx].first_cluster, editor_buffer,
              file_cache[file_idx].size < EDITOR_BUFFER_SIZE
                  ? file_cache[file_idx].size
                  : EDITOR_BUFFER_SIZE);
    buffer_pos = file_cache[file_idx].size;
  }
  for (int i = buffer_pos; i < EDITOR_BUFFER_SIZE; i++)
    editor_buffer[i] = ' ';

  int cursor_row = 1;
  int cursor_col = 0;
  bool shift = false;
  bool running = true;

  while (running) {
    // MD Style Header
    draw_window(0, 0, 2, 80, " MillaWriter (MD) ", 0x0D); // Magenta
    print_string(0, 60, "F1:Save ESC:Exit", 0x1F);
    print_string(0, 2, filename, 0x1E);

    // Render loop with Markdown Syntax Highlighting
    for (int row = 1; row < 24; row++) {
      bool is_header = false;
      // Check start of line for #
      int line_start = (row - 1) * 80;
      if (line_start < EDITOR_BUFFER_SIZE && editor_buffer[line_start] == '#')
        is_header = true;

      for (int col = 0; col < 80; col++) {
        int pos = (row - 1) * 80 + col;
        if (pos < EDITOR_BUFFER_SIZE) {
          char c = editor_buffer[pos];
          if (c == '\n')
            c = ' ';
          uint16_t color = 0x0F;

          if (is_header)
            color = 0x0E; // Yellow for headers
          if (c == '*' || c == '_')
            color = 0x0A; // Green for syntax

          print_char(row, col, c, color);
        }
      }
    }
    print_char(cursor_row, cursor_col, 219, 0x0D);

    uint8_t sc = get_keyboard_input();

    if (sc == 0x01)
      running = false;
    else if (sc == 0x3B) { // F1 Save
      int actual_size = EDITOR_BUFFER_SIZE - 1;
      while (actual_size >= 0 && (editor_buffer[actual_size] == ' ' ||
                                  editor_buffer[actual_size] == '\0' ||
                                  editor_buffer[actual_size] == '\n'))
        actual_size--;
      write_file(active_disk, filename, editor_buffer, actual_size + 1);
      print_string(24, 60, "Saved!", 0x2A);
      delay(10);
    } else {
      // Standard edit logic
      if (sc == 0x2A || sc == 0x36)
        shift = true;
      else if (sc == 0xAA || sc == 0xB6)
        shift = false;
      else if (sc == 0x48 && cursor_row > 1)
        cursor_row--;
      else if (sc == 0x50 && cursor_row < 23)
        cursor_row++;
      else if (sc == 0x4B && cursor_col > 0)
        cursor_col--;
      else if (sc == 0x4D && cursor_col < 79)
        cursor_col++;
      else if (sc == 0x0E) { // Backspace
        int pos = (cursor_row - 1) * 80 + cursor_col;
        if (pos > 0) {
          if (cursor_col > 0)
            cursor_col--;
          else if (cursor_row > 1) {
            cursor_row--;
            cursor_col = 79;
          }
          int new_pos = (cursor_row - 1) * 80 + cursor_col;
          for (int i = new_pos; i < EDITOR_BUFFER_SIZE - 1; i++)
            editor_buffer[i] = editor_buffer[i + 1];
        }
      } else if (sc == 0x1C) { // Enter
        if (cursor_row < 23) {
          cursor_row++;
          cursor_col = 0;
        }
      } else {
        char c = scancode_to_ascii(sc, shift);
        if (c != 0) {
          int pos = (cursor_row - 1) * 80 + cursor_col;
          if (pos < EDITOR_BUFFER_SIZE) {
            editor_buffer[pos] = c;
            if (cursor_col < 79)
              cursor_col++;
            else if (cursor_row < 23) {
              cursor_row++;
              cursor_col = 0;
            }
          }
        }
      }
    }
  }
}

// ============================================================================
// SOLITAIRE GAME
// ============================================================================

struct Card {
  uint8_t rank; // 0=A, 1=2, ... 9=10, 10=J, 11=Q, 12=K
  uint8_t suit; // 0=HEARTS, 1=DIAMONDS, 2=CLUBS, 3=SPADES
  bool face_up;
};

// Game State
Card piles[13][52]; // 0-6: Tableau, 7-10: Foundation, 11: Stock, 12: Waste
int pile_counts[13];

// Random need seed from time or user interaction
void shuffle_deck(Card *deck, int count) {
  for (int i = 0; i < count; i++) {
    int r = milla_rand(0, count - 1);
    Card temp = deck[i];
    deck[i] = deck[r];
    deck[r] = temp;
  }
}

void init_solitaire() {
  Card full_deck[52];
  int idx = 0;
  for (int s = 0; s < 4; s++) {
    for (int r = 0; r < 13; r++) {
      full_deck[idx].rank = r;
      full_deck[idx].suit = s;
      full_deck[idx].face_up = false;
      idx++;
    }
  }
  shuffle_deck(full_deck, 52);

  int card_idx = 0;
  for (int i = 0; i < 7; i++) {
    pile_counts[i] = i + 1;
    for (int j = 0; j < i + 1; j++) {
      piles[i][j] = full_deck[card_idx++];
      if (j == i)
        piles[i][j].face_up = true;
    }
  }

  pile_counts[11] = 0;
  while (card_idx < 52) {
    piles[11][pile_counts[11]] = full_deck[card_idx++];
    piles[11][pile_counts[11]].face_up = false;
    pile_counts[11]++;
  }

  for (int i = 7; i <= 10; i++)
    pile_counts[i] = 0;
  pile_counts[12] = 0;
}

void draw_card(int row, int col, Card c, bool selected) {
  uint16_t bg = selected ? 0x20 : 0x70;
  if (!c.face_up) {
    print_string(row, col, "[##]", 0x1F | (selected ? 0x20 : 0x00));
    return;
  }

  uint16_t color = (c.suit < 2) ? 0x0C : 0x00;
  color |= bg;

  char face[5];
  face[0] = '[';
  int pos = 1;
  if (c.rank == 0)
    face[pos++] = 'A';
  else if (c.rank >= 1 && c.rank <= 8)
    face[pos++] = '1' + c.rank;
  else if (c.rank == 9) {
    face[pos++] = '1';
    face[pos++] = '0';
  } else if (c.rank == 10)
    face[pos++] = 'J';
  else if (c.rank == 11)
    face[pos++] = 'Q';
  else if (c.rank == 12)
    face[pos++] = 'K';

  face[pos++] = 3 + c.suit;
  face[pos++] = ']';
  face[pos] = '\0';

  print_string(row, col, face, color);
}

void draw_placeholder(int row, int col, bool selected) {
  uint16_t color = selected ? 0x2F : 0x70;
  print_string(row, col, "[  ]", color);
}

void solitaire() {
  init_solitaire();

  int cur_pile = 0;
  int src_pile = -1;
  bool running = true;
  bool redraw = true;
  for (int i = 0; i < (get_keyboard_input() % 10); i++)
    milla_rand(0, 10);

  while (running) {
    if (redraw) {
      clear_screen(0x03);
      print_string(0, 0, " MillaSolitaire ", 0x3F);
      print_string(0, 60, "Arrows=Move SPC=Sel Q=Quit", 0x3F);

      if (pile_counts[11] > 0)
        draw_card(2, 2, piles[11][pile_counts[11] - 1], cur_pile == 11);
      else
        draw_placeholder(2, 2, cur_pile == 11);
      if (cur_pile == 11 && pile_counts[11] == 0)
        print_string(3, 2, "R", 0x30);

      if (pile_counts[12] > 0)
        draw_card(2, 8, piles[12][pile_counts[12] - 1], cur_pile == 12);
      else
        draw_placeholder(2, 8, cur_pile == 12);

      for (int i = 0; i < 4; i++) {
        int pid = 7 + i;
        int col = 30 + i * 6;
        if (pile_counts[pid] > 0)
          draw_card(2, col, piles[pid][pile_counts[pid] - 1], cur_pile == pid);
        else {
          draw_placeholder(2, col, cur_pile == pid);
          char s[2] = {(char)(3 + i), 0};
          print_string(2, col + 1, s, (i < 2 ? 0x0C : 0x00) | 0x70);
        }
      }

      for (int i = 0; i < 7; i++) {
        int col = 2 + i * 8;
        if (pile_counts[i] == 0) {
          draw_placeholder(6, col, cur_pile == i && src_pile != i);
        } else {
          for (int j = 0; j < pile_counts[i]; j++) {
            int row = 6 + j;
            if (row > 23)
              row = 23;
            bool is_top = (j == pile_counts[i] - 1);
            bool selected = (cur_pile == i && is_top);
            if (src_pile == i && is_top)
              selected = true;

            draw_card(row, col, piles[i][j], selected);
          }
        }
        if (pile_counts[i] == 0 && cur_pile == i) {
          draw_placeholder(6, col, true);
        }
      }

      if (src_pile != -1) {
        char status[30];
        string_copy(status, "Selected: ");
        if (src_pile == 11)
          string_copy(status + 10, "Stock");
        else if (src_pile == 12)
          string_copy(status + 10, "Waste");
        else if (src_pile < 7) {
          string_copy(status + 10, "Col");
          status[13] = '1' + src_pile;
          status[14] = 0;
        }
        print_string(24, 2, status, 0x1E);
      }
      redraw = false;
    }

    uint8_t sc = get_keyboard_input();

    if (sc == 0x01 || sc == 0x10) {
      running = false;
    } else if (sc == 0x4B) {
      if (cur_pile == 7)
        cur_pile = 12;
      else if (cur_pile == 12)
        cur_pile = 11;
      else if (cur_pile > 0 && cur_pile < 7)
        cur_pile--;
      else if (cur_pile > 7)
        cur_pile--;
      else if (cur_pile == 0)
        cur_pile = 6;
      redraw = true;
    } else if (sc == 0x4D) {
      if (cur_pile == 11)
        cur_pile = 12;
      else if (cur_pile == 12)
        cur_pile = 7;
      else if (cur_pile < 6)
        cur_pile++;
      else if (cur_pile >= 7 && cur_pile < 10)
        cur_pile++;
      else if (cur_pile == 10)
        cur_pile = 0;
      redraw = true;
    } else if (sc == 0x48) {
      if (cur_pile < 7) {
        if (cur_pile < 2)
          cur_pile = 11 + cur_pile;
        else
          cur_pile = 7 + (cur_pile - 3);
        if (cur_pile > 10)
          cur_pile = 10;
      }
      redraw = true;
    } else if (sc == 0x50) {
      if (cur_pile >= 7) {
        cur_pile = (cur_pile - 7) * 2;
        if (cur_pile > 6)
          cur_pile = 6;
      }
      redraw = true;
    } else if (sc == 0x39 || sc == 0x1C) {
      if (cur_pile == 11) {
        if (pile_counts[11] > 0) {
          Card c = piles[11][pile_counts[11] - 1];
          pile_counts[11]--;
          c.face_up = true;
          piles[12][pile_counts[12]] = c;
          pile_counts[12]++;
        } else {
          if (pile_counts[12] > 0) {
            for (int i = pile_counts[12] - 1; i >= 0; i--) {
              Card c = piles[12][i];
              c.face_up = false;
              piles[11][pile_counts[11]] = c;
              pile_counts[11]++;
            }
            pile_counts[12] = 0;
          }
        }
        if (src_pile == 11)
          src_pile = -1;
        redraw = true;
      } else {
        if (src_pile == -1) {
          if (pile_counts[cur_pile] > 0) {
            src_pile = cur_pile;
            redraw = true;
          }
        } else {
          if (src_pile == cur_pile) {
            src_pile = -1;
            redraw = true;
          } else {
            Card src = piles[src_pile][pile_counts[src_pile] - 1];
            bool valid = false;

            if (cur_pile >= 7 && cur_pile <= 10) {
              if (pile_counts[cur_pile] == 0) {
                if (src.rank == 0)
                  valid = true;
              } else {
                Card top = piles[cur_pile][pile_counts[cur_pile] - 1];
                if (top.suit == src.suit && src.rank == top.rank + 1)
                  valid = true;
              }
            } else if (cur_pile < 7) {
              if (pile_counts[cur_pile] == 0) {
                if (src.rank == 12)
                  valid = true;
              } else {
                Card top = piles[cur_pile][pile_counts[cur_pile] - 1];
                bool src_red = (src.suit < 2);
                bool top_red = (top.suit < 2);
                if (src_red != top_red && src.rank == top.rank - 1)
                  valid = true;
              }
            }

            if (valid) {
              piles[cur_pile][pile_counts[cur_pile]++] = src;
              pile_counts[src_pile]--;
              if (src_pile < 7 && pile_counts[src_pile] > 0) {
                piles[src_pile][pile_counts[src_pile] - 1].face_up = true;
              }
              src_pile = -1;
              redraw = true;
            }
          }
        }
      }
    }
  }
}

// ============================================================================
// HAUPTMENÜ
// ============================================================================

void main_menu() {
  clear_screen(0x03);

  int win_height = 20;
  int win_width = 40;
  int win_y = 3;
  int win_x = 20;

  for (int i = 0; i < 80; i++)
    print_char(0, i, ' ', 0x1F);
  print_string(0, 2, "Milla OS 1.0 - Start Menu", 0x1E);

  draw_window(win_y, win_x, win_height, win_width, " Main Menu ", 0x0B);

  // **GEÄNDERT: Menüpunkte**
  const char *menu_items[] = {
      "1. File Manager", "2. Doc Writer", "3. Calculator", "4. Milla Lang",
      "5. Milla IDE",    "6. Solitaire",  "7. Settings",   "8. Exit to MTop"};

  const int NUM_ITEMS = 8;

  int selected = 0;
  bool running = true;

  while (running) {
    // Menü neu zeichnen (wichtig nach get_string_input)
    draw_window(win_y, win_x, win_height, win_width, " Main Menu ", 0x0B);

    // Draw Background
    for (int r = win_y + 1; r < win_y + win_height - 1; r++) {
      for (int c = win_x + 1; c < win_x + win_width - 1; c++)
        print_char(r, c, ' ', 0x0F);
    }

    for (int i = 0; i < NUM_ITEMS; i++) {
      int item_y = win_y + 2 + (i * 2);
      uint16_t color = (i == selected) ? 0x4E : 0x0F;
      if (i == selected) {
        for (int k = 0; k < win_width - 2; k++)
          print_char(item_y, win_x + 1 + k, ' ', 0x4F);
      }
      print_string(item_y, win_x + 3, menu_items[i], color);
    }

    for (int i = 0; i < 80; i++)
      print_char(24, i, ' ', 0x70);
    print_string(24, 2, "UP/DOWN=Select ENTER=Open ESC=MTop", 0x70);

    uint8_t scancode = get_keyboard_input();

    if (scancode == 0x01) {
      running = false;
    } else if (scancode == 0x48 && selected > 0) {
      selected--;
    } else if (scancode == 0x50 && selected < NUM_ITEMS - 1) {
      selected++;
    } else if (scancode == 0x1C) {
      switch (selected) {
      case 0:
        file_manager();
        break;
      case 1: // DOC EDITOR / TEXT Editor
      {
        // Ask filename etc.
        char filename_buffer[MAX_FILENAME + 1];
        memset(filename_buffer, 0, sizeof(filename_buffer));
        get_string_input(10, 20, 40, " Enter Filename ", filename_buffer,
                         MAX_FILENAME);
        if (string_length(filename_buffer) == 0)
          string_copy(filename_buffer, "NEW.MD");

        // Auto extension
        // If not .MC and not .TXT, assume .MD for this menu item?
        // Let's just launch doc_editor
        const char *ext = get_filename_ext(filename_buffer);
        if (string_length(ext) == 0) {
          // Append .MD by default for Doc Writer
          int len = string_length(filename_buffer);
          if (len < MAX_FILENAME - 3) {
            filename_buffer[len] = '.';
            filename_buffer[len + 1] = 'M';
            filename_buffer[len + 2] = 'D';
            filename_buffer[len + 3] = '\0';
          }
        }

        doc_editor(filename_buffer);
      } break;
      case 2:
        calculator();
        break;
      case 3:
        milla_lang();
        break;
      case 4:
        // IDE Launch from menu (already handled above in full logic but
        // previous chunk missed case 5 label in this snippet) Wait, I need to
        // match properly.
        {
          char filename_buffer[MAX_FILENAME + 1];
          memset(filename_buffer, 0, sizeof(filename_buffer));
          get_string_input(10, 20, 40, " Enter MC File ", filename_buffer,
                           MAX_FILENAME);
          if (string_length(filename_buffer) == 0)
            string_copy(filename_buffer, "SCRIPT.MC");

          const char *ext = get_filename_ext(filename_buffer);
          if (string_length(ext) == 0) {
            int len = string_length(filename_buffer);
            if (len < MAX_FILENAME - 3) {
              filename_buffer[len] = '.';
              filename_buffer[len + 1] = 'M';
              filename_buffer[len + 2] = 'C';
              filename_buffer[len + 3] = '\0';
            }
          }
          milla_ide(filename_buffer);
        }
        break;
      case 5:
        solitaire();
        break;
      case 6:
        settings();
        break;
      case 7:
        running = false;
        break;
      }

      clear_screen(0x03);
      for (int i = 0; i < 80; i++)
        print_char(0, i, ' ', 0x1F);
      print_string(0, 2, "Milla OS 1.0 - Start Menu", 0x1E);
      draw_window(win_y, win_x, win_height, win_width, " Main Menu ", 0x0B);
    }
  }
}

// ============================================================================
// MTop
// ============================================================================

void MTop() {
  clear_screen(0x03);

  for (int i = 0; i < 80; i++)
    print_char(0, i, ' ', 0x1F);
  print_string(0, 2, "Milla OS 1.0", 0x1E);
  print_string(0, 60, "[F1=STARTMENU]", 0x4F);

  // WIDGET: Clock
  Time t = get_time();
  char time_str[9] = "00:00:00";
  time_str[0] = '0' + (t.hour / 10);
  time_str[1] = '0' + (t.hour % 10);
  time_str[3] = '0' + (t.minute / 10);
  time_str[4] = '0' + (t.minute % 10);
  time_str[6] = '0' + (t.second / 10);
  time_str[7] = '0' + (t.second % 10);
  print_string(0, 45, time_str, 0x1E);

  // WIDGET: Stats
  print_string(0, 30, "RAM: 1MB", 0x1E);

  draw_window(3, 10, 12, 60, " MTOP ", 0x0B);
  print_string(5, 15, "Welcome to Milla OS!", 0x70);
  // print_string(6, "(Micro Integrated Low-Level Application OS)", 0x70);

  print_string(8, 15, "A FOSS Operating System", 0x78);
  print_string(9, 15, "by FloriDevs", 0x78);
  print_string(11, 15, "Press F1 for Menu", 0x70);

  for (int i = 0; i < 80; i++)
    print_char(24, i, ' ', 0x70);

  char status[50] = "Ready - Active Disk: ";
  // **GEÄNDERT: Nur noch MRD0**
  if (active_disk == &ramdisk_device) {
    string_copy(status + 21, "MRD0 (");
  } else {
    string_copy(status + 21, "None (");
  }

  if (active_disk) {
    if (fs_mounted) {
      string_copy(status + string_length(status), "Mounted)");
      print_string(11, 15, "Ramdisk filesystem ready", 0x70);
    } else {
      string_copy(status + string_length(status), "Unformatted)");
      print_string(11, 15, "Disk found. Format needed.", 0x70);
    }
  } else {
    string_copy(status + 21, "Not found");
    print_string(11, 15, "No disk found.", 0x70);
  }
  print_string(24, 2, status, 0x70);

  int cursor_row = 12;
  int cursor_col = 40;

  while (1) {
    // UPDATE CLOCK WIDGET loop
    Time t = get_time();
    char time_str[9] = "00:00:00";
    time_str[0] = '0' + (t.hour / 10);
    time_str[1] = '0' + (t.hour % 10);
    time_str[3] = '0' + (t.minute / 10);
    time_str[4] = '0' + (t.minute % 10);
    time_str[6] = '0' + (t.second / 10);
    time_str[7] = '0' + (t.second % 10);
    print_string(0, 45, time_str, 0x1E);

    print_char(cursor_row, cursor_col, 219, 0x0E);

    char cursor_status[30] = "Cursor: [  ,  ]";
    cursor_status[9] = '0' + (cursor_row / 10);
    cursor_status[10] = '0' + (cursor_row % 10);
    cursor_status[12] = '0' + (cursor_col / 10);
    cursor_status[13] = '0' + (cursor_col % 10);
    print_string(24, 60, cursor_status, 0x70);

    uint8_t scancode = get_keyboard_input();

    print_char(cursor_row, cursor_col, ' ', 0x03);

    if (scancode == 0x3B) { // F1
      main_menu();
      // MTop neu zeichnen
      clear_screen(0x03);
      for (int i = 0; i < 80; i++)
        print_char(0, i, ' ', 0x1F);
      print_string(0, 2, "Milla OS 1.0", 0x1E);
      print_string(0, 60, "[F1=MENU]", 0x4F);
      draw_window(3, 10, 12, 60, " Welcome ", 0x0B);
      print_string(5, 15, "Welcome to Milla OS!", 0x70);
      print_string(7, 15, "A FOSS Operating System", 0x78);
      print_string(8, 15, "by FloriDevs", 0x78);
      print_string(10, 15, "Press F1 for Menu", 0x70);

      for (int i = 0; i < 80; i++)
        print_char(24, i, ' ', 0x70);

      // Status neu setzen
      char status2[50] = "Ready - Active Disk: ";
      // **GEÄNDERT: Nur noch MRD0**
      if (active_disk == &ramdisk_device) {
        string_copy(status2 + 21, "MRD0 (");
      } else {
        string_copy(status2 + 21, "None (");
      }
      if (active_disk) {
        if (fs_mounted) {
          string_copy(status2 + string_length(status2), "Mounted)");
          print_string(11, 15, "FAT16 filesystem ready", 0x70);
        } else {
          string_copy(status2 + string_length(status2), "Unformatted)");
          print_string(11, 15, "Disk found. Format needed.", 0x70);
        }
      } else {
        string_copy(status2 + 21, "Not found");
        print_string(11, 15, "No disk found.", 0x70);
      }
      print_string(24, 2, status2, 0x70);

    } else if (scancode == 0x4B && cursor_col > 0) {
      cursor_col--;
    } else if (scancode == 0x4D && cursor_col < 79) {
      cursor_col++;
    } else if (scancode == 0x48 && cursor_row > 1) {
      cursor_row--;
    } else if (scancode == 0x50 && cursor_row < 23) {
      cursor_row++;
    }
  }
}

// ============================================================================
// KERNEL MAIN
// ============================================================================

extern "C" void kernel_main(uint32_t magic, multiboot_info *info) {
  // Initialize mouse early
  init_mouse();

  // Initialize graphics if available
  screen.active = false;

  if (magic == 0x2BADB002) {
    // Priority 1: Modern Framebuffer Tag (Bit 12)
    if (info->flags & (1 << 12)) {
      screen.framebuffer = (uint32_t *)(uintptr_t)info->framebuffer_addr;
      screen.width = info->framebuffer_width;
      screen.height = info->framebuffer_height;
      screen.pitch = info->framebuffer_pitch;
      screen.active = true;
    }
    // Priority 2: VBE Tag (Bit 11)
    else if (info->flags & (1 << 11)) {
      vbe_mode_info *vbe = (vbe_mode_info *)(uintptr_t)info->vbe_mode_info;
      if (vbe->framebuffer != 0) {
        screen.framebuffer = (uint32_t *)(uintptr_t)vbe->framebuffer;
        screen.width = vbe->x_res;
        screen.height = vbe->y_res;
        screen.pitch = vbe->bytes_per_scanline;
        screen.active = true;
      }
    }
  }

  // Calculate RAM size from multiboot info
  if (magic == 0x2BADB002) {
    if (info->flags & 1) {
      // mem_upper is KB above 1MB
      system_ram_mb = (info->mem_upper + 1024) / 1024;
    }
  }
  if (system_ram_mb == 0)
    system_ram_mb = 128; // Fallback

  if (screen.active) {
    // We will call the graphical shell here
    // For now, let's just clear the screen to a modern dark grey
    // Clear screen efficiently
    if (screen.framebuffer) {
      uint32_t total_pixels = screen.width * screen.height;
      for (uint32_t i = 0; i < total_pixels; i++) {
        screen.framebuffer[i] = 0x1A1A1A;
      }
    }
    init_filesystem();
    start_graphical_shell();

    // Fallback if shell returns
    // draw_flower();
    // MTop();
  } else {
    draw_flower();
    init_filesystem();
    MTop();
  }
}

// ***ENDE CODE***